diff --git a/CHANGES b/CHANGES
index f01124afd8..16d64dd962 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,9 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
 
+  *) mod_http2: input buffering and dynamic flow windows for increased 
+     throughput. [Stefan Eissing]
+
   *) mod_http2: h2 workers with improved scalability for better scheduling
      performance. There are H2MaxWorkers threads created at start and the
      number is kept constant. [Stefan Eissing]
diff --git a/modules/http2/h2.h b/modules/http2/h2.h
index 21a673244f..df809fd411 100644
--- a/modules/http2/h2.h
+++ b/modules/http2/h2.h
@@ -115,7 +115,8 @@ typedef enum {
     H2_SEV_CLOSED_L,
     H2_SEV_CLOSED_R,
     H2_SEV_CANCELLED,
-    H2_SEV_EOS_SENT
+    H2_SEV_EOS_SENT,
+    H2_SEV_IN_DATA_PENDING,
 } h2_stream_event_t;
 
 
diff --git a/modules/http2/h2_bucket_beam.c b/modules/http2/h2_bucket_beam.c
index 16f0a049d7..7fb6cb6f79 100644
--- a/modules/http2/h2_bucket_beam.c
+++ b/modules/http2/h2_bucket_beam.c
@@ -246,15 +246,17 @@ static int report_consumption(h2_bucket_beam *beam, h2_beam_lock *pbl)
     apr_off_t len = beam->received_bytes - beam->cons_bytes_reported;
     h2_beam_io_callback *cb = beam->cons_io_cb;
      
-    if (cb) {
-        void *ctx = beam->cons_ctx;
-        
-        if (pbl) leave_yellow(beam, pbl);
-        cb(ctx, beam, len);
-        if (pbl) enter_yellow(beam, pbl);
-        rv = 1;
+    if (len > 0) {
+        if (cb) {
+            void *ctx = beam->cons_ctx;
+            
+            if (pbl) leave_yellow(beam, pbl);
+            cb(ctx, beam, len);
+            if (pbl) enter_yellow(beam, pbl);
+            rv = 1;
+        }
+        beam->cons_bytes_reported += len;
     }
-    beam->cons_bytes_reported += len;
     return rv;
 }
 
@@ -1250,9 +1252,9 @@ void h2_beam_log(h2_bucket_beam *beam, conn_rec *c, int level, const char *msg)
     if (beam && APLOG_C_IS_LEVEL(c,level)) {
         ap_log_cerror(APLOG_MARK, level, 0, c, 
                       "beam(%ld-%d,%s,closed=%d,aborted=%d,empty=%d,buf=%ld): %s", 
-                      c->id, beam->id, beam->tag, beam->closed, beam->aborted, 
-                      h2_beam_empty(beam), (long)h2_beam_get_buffered(beam),
-                      msg);
+                      (c->master? c->master->id : c->id), beam->id, beam->tag, 
+                      beam->closed, beam->aborted, h2_beam_empty(beam), 
+                      (long)h2_beam_get_buffered(beam), msg);
     }
 }
 
diff --git a/modules/http2/h2_filter.c b/modules/http2/h2_filter.c
index 617d350d59..3a8a3b1ad1 100644
--- a/modules/http2/h2_filter.c
+++ b/modules/http2/h2_filter.c
@@ -44,55 +44,80 @@
 #define UNSET       -1
 #define H2MIN(x,y) ((x) < (y) ? (x) : (y))
 
-static apr_status_t consume_brigade(h2_filter_cin *cin, 
-                                    apr_bucket_brigade *bb, 
-                                    apr_read_type_e block)
+static apr_status_t recv_RAW_DATA(conn_rec *c, h2_filter_cin *cin, 
+                                  apr_bucket *b, apr_read_type_e block)
 {
+    h2_session *session = cin->session;
     apr_status_t status = APR_SUCCESS;
-    apr_size_t readlen = 0;
+    apr_size_t len;
+    const char *data;
+    ssize_t n;
     
-    while (status == APR_SUCCESS && !APR_BRIGADE_EMPTY(bb)) {
+    status = apr_bucket_read(b, &data, &len, block);
+    
+    while (status == APR_SUCCESS && len > 0) {
+        n = nghttp2_session_mem_recv(session->ngh2, (const uint8_t *)data, len);
         
-        apr_bucket* bucket = APR_BRIGADE_FIRST(bb);
-        if (APR_BUCKET_IS_METADATA(bucket)) {
-            /* we do nothing regarding any meta here */
-        }
-        else {
-            const char *bucket_data = NULL;
-            apr_size_t bucket_length = 0;
-            status = apr_bucket_read(bucket, &bucket_data,
-                                     &bucket_length, block);
-            
-            if (status == APR_SUCCESS && bucket_length > 0) {
-                apr_size_t consumed = 0;
-
-                status = cin->cb(cin->cb_ctx, bucket_data, bucket_length, &consumed);
-                if (status == APR_SUCCESS && bucket_length > consumed) {
-                    /* We have data left in the bucket. Split it. */
-                    status = apr_bucket_split(bucket, consumed);
-                }
-                readlen += consumed;
-                cin->start_read = apr_time_now();
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, session->c,
+                      H2_SSSN_MSG(session, "fed %ld bytes to nghttp2, %ld read"),
+                      (long)len, (long)n);
+        if (n < 0) {
+            if (nghttp2_is_fatal((int)n)) {
+                h2_session_event(session, H2_SESSION_EV_PROTO_ERROR, 
+                                 (int)n, nghttp2_strerror((int)n));
+                status = APR_EGENERAL;
             }
         }
-        apr_bucket_delete(bucket);
+        else {
+            session->io.bytes_read += n;
+            if (len <= n) {
+                break;
+            }
+            len -= n;
+            data += n;
+        }
     }
     
-    if (readlen == 0 && status == APR_SUCCESS && block == APR_NONBLOCK_READ) {
+    return status;
+}
+
+static apr_status_t recv_RAW_brigade(conn_rec *c, h2_filter_cin *cin, 
+                                     apr_bucket_brigade *bb, 
+                                     apr_read_type_e block)
+{
+    apr_status_t status = APR_SUCCESS;
+    apr_bucket* b;
+    int consumed = 0;
+    
+    h2_util_bb_log(c, c->id, APLOG_TRACE2, "RAW_in", bb);
+    while (status == APR_SUCCESS && !APR_BRIGADE_EMPTY(bb)) {
+        b = APR_BRIGADE_FIRST(bb);
+
+        if (APR_BUCKET_IS_METADATA(b)) {
+            /* nop */
+        }
+        else {
+            status = recv_RAW_DATA(c, cin, b, block);
+        }
+        consumed = 1;
+        apr_bucket_delete(b);
+    }
+    
+    if (!consumed && status == APR_SUCCESS && block == APR_NONBLOCK_READ) {
         return APR_EAGAIN;
     }
     return status;
 }
 
-h2_filter_cin *h2_filter_cin_create(apr_pool_t *p, h2_filter_cin_cb *cb, void *ctx)
+h2_filter_cin *h2_filter_cin_create(h2_session *session)
 {
     h2_filter_cin *cin;
     
-    cin = apr_pcalloc(p, sizeof(*cin));
-    cin->pool      = p;
-    cin->cb        = cb;
-    cin->cb_ctx    = ctx;
-    cin->start_read = UNSET;
+    cin = apr_pcalloc(session->pool, sizeof(*cin));
+    if (!cin) {
+        return NULL;
+    }
+    cin->session = session;
     return cin;
 }
 
@@ -110,11 +135,14 @@ apr_status_t h2_filter_core_input(ap_filter_t* f,
     h2_filter_cin *cin = f->ctx;
     apr_status_t status = APR_SUCCESS;
     apr_interval_time_t saved_timeout = UNSET;
+    const int trace1 = APLOGctrace1(f->c);
     
-    ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, f->c,
-                  "h2_session(%ld): read, %s, mode=%d, readbytes=%ld", 
-                  (long)f->c->id, (block == APR_BLOCK_READ)? 
-                  "BLOCK_READ" : "NONBLOCK_READ", mode, (long)readbytes);
+    if (trace1) {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, f->c,
+                      "h2_session(%ld): read, %s, mode=%d, readbytes=%ld", 
+                      (long)f->c->id, (block == APR_BLOCK_READ)? 
+                      "BLOCK_READ" : "NONBLOCK_READ", mode, (long)readbytes);
+    }
     
     if (mode == AP_MODE_INIT || mode == AP_MODE_SPECULATIVE) {
         return ap_get_brigade(f->next, brigade, mode, block, readbytes);
@@ -125,20 +153,16 @@ apr_status_t h2_filter_core_input(ap_filter_t* f,
     }
     
     if (!cin->bb) {
-        cin->bb = apr_brigade_create(cin->pool, f->c->bucket_alloc);
+        cin->bb = apr_brigade_create(cin->session->pool, f->c->bucket_alloc);
     }
 
     if (!cin->socket) {
         cin->socket = ap_get_conn_socket(f->c);
     }
     
-    cin->start_read = apr_time_now();
     if (APR_BRIGADE_EMPTY(cin->bb)) {
         /* We only do a blocking read when we have no streams to process. So,
          * in httpd scoreboard lingo, we are in a KEEPALIVE connection state.
-         * When reading non-blocking, we do have streams to process and update
-         * child with NULL request. That way, any current request information
-         * in the scoreboard is preserved.
          */
         if (block == APR_BLOCK_READ) {
             if (cin->timeout > 0) {
@@ -155,13 +179,15 @@ apr_status_t h2_filter_core_input(ap_filter_t* f,
     
     switch (status) {
         case APR_SUCCESS:
-            status = consume_brigade(cin, cin->bb, block);
+            status = recv_RAW_brigade(f->c, cin, cin->bb, block);
             break;
         case APR_EOF:
         case APR_EAGAIN:
         case APR_TIMEUP:
-            ap_log_cerror(APLOG_MARK, APLOG_TRACE1, status, f->c,
-                          "h2_session(%ld): read", f->c->id);
+            if (trace1) {
+                ap_log_cerror(APLOG_MARK, APLOG_TRACE1, status, f->c,
+                              "h2_session(%ld): read", f->c->id);
+            }
             break;
         default:
             ap_log_cerror(APLOG_MARK, APLOG_DEBUG, status, f->c, APLOGNO(03046)
diff --git a/modules/http2/h2_filter.h b/modules/http2/h2_filter.h
index b3e34cc5ba..093d4ea3bc 100644
--- a/modules/http2/h2_filter.h
+++ b/modules/http2/h2_filter.h
@@ -21,21 +21,16 @@ struct h2_headers;
 struct h2_stream;
 struct h2_session;
 
-typedef apr_status_t h2_filter_cin_cb(void *ctx, 
-                                      const char *data, apr_size_t len,
-                                      apr_size_t *readlen);
-
 typedef struct h2_filter_cin {
     apr_pool_t *pool;
-    apr_bucket_brigade *bb;
-    h2_filter_cin_cb *cb;
-    void *cb_ctx;
     apr_socket_t *socket;
     apr_interval_time_t timeout;
-    apr_time_t start_read;
+    apr_bucket_brigade *bb;
+    struct h2_session *session;
+    apr_bucket *cur;
 } h2_filter_cin;
 
-h2_filter_cin *h2_filter_cin_create(apr_pool_t *p, h2_filter_cin_cb *cb, void *ctx);
+h2_filter_cin *h2_filter_cin_create(struct h2_session *session);
 
 void h2_filter_cin_timeout_set(h2_filter_cin *cin, apr_interval_time_t timeout);
 
diff --git a/modules/http2/h2_mplx.c b/modules/http2/h2_mplx.c
index 14f42d4d28..2251dcb510 100644
--- a/modules/http2/h2_mplx.c
+++ b/modules/http2/h2_mplx.c
@@ -618,6 +618,18 @@ static apr_status_t out_close(h2_mplx *m, h2_task *task)
     return status;
 }
 
+static int report_input_consumption(void *ctx, void *val)
+{
+    h2_stream *stream = val;
+    
+    (void)ctx;
+    if (stream->input) {
+        h2_beam_report_consumption(stream->input);
+    }
+    return 1;
+}
+
+
 apr_status_t h2_mplx_out_trywait(h2_mplx *m, apr_interval_time_t timeout,
                                  apr_thread_cond_t *iowait)
 {
@@ -633,6 +645,7 @@ apr_status_t h2_mplx_out_trywait(h2_mplx *m, apr_interval_time_t timeout,
         }
         else {
             purge_streams(m);
+            h2_ihash_iter(m->streams, report_input_consumption, m);
             m->added_output = iowait;
             status = apr_thread_cond_timedwait(m->added_output, m->lock, timeout);
             if (APLOGctrace2(m->c)) {
diff --git a/modules/http2/h2_session.c b/modules/http2/h2_session.c
index 4c5a3c5322..d05d998e10 100644
--- a/modules/http2/h2_session.c
+++ b/modules/http2/h2_session.c
@@ -56,6 +56,7 @@ static void transit(h2_session *session, const char *action,
 
 static void on_stream_state_enter(void *ctx, h2_stream *stream);
 static void on_stream_state_event(void *ctx, h2_stream *stream, h2_stream_event_t ev);
+static void on_stream_event(void *ctx, h2_stream *stream, h2_stream_event_t ev);
 
 static int h2_session_status_from_apr_status(apr_status_t rv)
 {
@@ -71,26 +72,79 @@ static int h2_session_status_from_apr_status(apr_status_t rv)
     return NGHTTP2_ERR_PROTO;
 }
 
+static h2_stream *get_stream(h2_session *session, int stream_id)
+{
+    return nghttp2_session_get_stream_user_data(session->ngh2, stream_id);
+}
+
 static void update_window(void *ctx, int stream_id, apr_off_t bytes_read)
 {
-    h2_session *session = (h2_session*)ctx;
-    while (bytes_read > 0) {
-        int len = (bytes_read > INT_MAX)? INT_MAX : bytes_read;
-        nghttp2_session_consume(session->ngh2, stream_id, (int)bytes_read);
-        ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, session->c,
-                      "h2_stream(%ld-%d): consumed %d bytes",
-                      session->id, stream_id, len);
-        bytes_read -= len;
+    h2_session *session = ctx;
+    
+    if (bytes_read > 0) {
+        h2_stream *stream = get_stream(session, stream_id);
+        apr_off_t consumed = bytes_read;
+        
+        while (consumed > 0) {
+            int len = (bytes_read > INT_MAX)? INT_MAX : bytes_read;
+            nghttp2_session_consume(session->ngh2, stream_id, (int)bytes_read);
+            consumed -= len;
+        }
+
+        if (stream) {
+            int cur_size = nghttp2_session_get_stream_local_window_size(
+                session->ngh2, stream->id);
+            int win = stream->in_window_size;
+            int thigh = win * 8/10;
+            int tlow = win * 2/10;
+            const int win_max = 2*1024*1024;
+            const int win_min = 32*1024;
+            
+            /* Work in progress, probably shoud add directives for these
+             * values once this stabilizes somewhat. The general idea is
+             * to adapt stream window sizes if the input window changes
+             * a) very quickly (< good RTT) from full to empty
+             * b) only a little bit (> bad RTT)
+             * where in a) it grows and in b) it shrinks again.
+             */
+            if (cur_size > thigh && bytes_read > thigh && win < win_max) {
+                /* almost empty again with one reported consumption, how
+                 * long did this take? */
+                long ms = apr_time_msec(apr_time_now() - stream->in_last_write);
+                if (ms < 40) {
+                    win = H2MIN(win_max, win + (64*1024));
+                }
+            }
+            else if (cur_size < tlow && bytes_read < tlow && win > win_min) {
+                /* staying full, for how long already? */
+                long ms = apr_time_msec(apr_time_now() - stream->in_last_write);
+                if (ms > 700) {
+                    win = H2MAX(win_min, win - (32*1024));
+                }
+            }
+            
+            if (win != stream->in_window_size) {
+                stream->in_window_size = win;
+                nghttp2_session_set_local_window_size(session->ngh2, 
+                        NGHTTP2_FLAG_NONE, stream_id, win);
+            } 
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, session->c,
+                          "h2_stream(%ld-%d): consumed %ld bytes, window now %d/%d",
+                          session->id, stream_id, (long)bytes_read, 
+                          cur_size, stream->in_window_size);
+        }
     }
 }
 
-static apr_status_t h2_session_receive(void *ctx, 
-                                       const char *data, apr_size_t len,
-                                       apr_size_t *readlen);
-
 static void dispatch_event(h2_session *session, h2_session_event_t ev, 
                              int err, const char *msg);
 
+void h2_session_event(h2_session *session, h2_session_event_t ev, 
+                             int err, const char *msg)
+{
+    dispatch_event(session, ev, err, msg);
+}
+
 static int rst_unprocessed_stream(h2_stream *stream, void *ctx)
 {
     int unprocessed = (!h2_stream_was_closed(stream)
@@ -227,11 +281,6 @@ static int on_invalid_frame_recv_cb(nghttp2_session *ngh2,
     return 0;
 }
 
-static h2_stream *get_stream(h2_session *session, int stream_id)
-{
-    return nghttp2_session_get_stream_user_data(session->ngh2, stream_id);
-}
-
 static int on_data_chunk_recv_cb(nghttp2_session *ngh2, uint8_t flags,
                                  int32_t stream_id,
                                  const uint8_t *data, size_t len, void *userp)
@@ -803,23 +852,35 @@ static apr_status_t h2_session_create_int(h2_session **psession,
         return status;
     }
     
+    session->in_pending = h2_iq_create(session->pool, session->max_stream_count);
+    if (session->in_pending == NULL) {
+        apr_pool_destroy(pool);
+        return APR_ENOMEM;
+    }
+
+    session->in_process = h2_iq_create(session->pool, session->max_stream_count);
+    if (session->in_process == NULL) {
+        apr_pool_destroy(pool);
+        return APR_ENOMEM;
+    }
+    
     session->monitor = apr_pcalloc(pool, sizeof(h2_stream_monitor));
     if (session->monitor == NULL) {
         apr_pool_destroy(pool);
-        return status;
+        return APR_ENOMEM;
     }
     session->monitor->ctx = session;
     session->monitor->on_state_enter = on_stream_state_enter;
     session->monitor->on_state_event = on_stream_state_event;
+    session->monitor->on_event = on_stream_event;
     
     session->mplx = h2_mplx_create(c, session->pool, session->config, 
                                    workers);
     
     h2_mplx_set_consumed_cb(session->mplx, update_window, session);
     
-    /* Install the connection input filter that feeds the session */
-    session->cin = h2_filter_cin_create(session->pool, 
-                                        h2_session_receive, session);
+    /* connection input filter that feeds the session */
+    session->cin = h2_filter_cin_create(session);
     ap_add_input_filter("H2_IN", session->cin, r, c);
     
     h2_conn_io_init(&session->io, c, session->config);
@@ -1431,7 +1492,8 @@ send_headers:
         if (!stream->has_response) {
             /* but no response */
             ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, session->c, 
-                          H2_STRM_LOG(APLOGNO(03466), stream, "no response, RST_STREAM"));
+                          H2_STRM_LOG(APLOGNO(03466), stream, 
+                          "no response, RST_STREAM"));
             h2_stream_rst(stream, H2_ERR_PROTOCOL_ERROR);
             return APR_SUCCESS;
         } 
@@ -1444,32 +1506,32 @@ send_headers:
     return status;
 }
 
-static apr_status_t h2_session_receive(void *ctx, const char *data, 
-                                       apr_size_t len, apr_size_t *readlen)
+static void h2_session_in_flush(h2_session *session)
 {
-    h2_session *session = ctx;
-    ssize_t n;
+    int id;
     
-    if (len > 0) {
-        ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, session->c,
-                      H2_SSSN_MSG(session, "feeding %ld bytes to nghttp2"),
-                      (long)len);
-        n = nghttp2_session_mem_recv(session->ngh2, (const uint8_t *)data, len);
-        if (n < 0) {
-            if (nghttp2_is_fatal((int)n)) {
-                dispatch_event(session, H2_SESSION_EV_PROTO_ERROR, (int)n, nghttp2_strerror((int)n));
-                return APR_EGENERAL;
+    while ((id = h2_iq_shift(session->in_process)) > 0) {
+        h2_stream *stream = get_stream(session, id);
+        if (stream) {
+            ap_assert(!stream->scheduled);
+            if (h2_stream_prep_processing(stream) == APR_SUCCESS) {
+                h2_mplx_process(session->mplx, stream, stream_pri_cmp, session);
+            }
+            else {
+                h2_stream_rst(stream, H2_ERR_INTERNAL_ERROR);
             }
         }
-        else {
-            *readlen = n;
-            session->io.bytes_read += n;
+    }
+
+    while ((id = h2_iq_shift(session->in_pending)) > 0) {
+        h2_stream *stream = get_stream(session, id);
+        if (stream) {
+            h2_stream_flush_input(stream);
         }
     }
-    return APR_SUCCESS;
 }
 
-static apr_status_t h2_session_read(h2_session *session, int block)
+static apr_status_t session_read(h2_session *session, apr_size_t readlen, int block)
 {
     apr_status_t status, rstatus = APR_EAGAIN;
     conn_rec *c = session->c;
@@ -1481,7 +1543,7 @@ static apr_status_t h2_session_read(h2_session *session, int block)
         status = ap_get_brigade(c->input_filters,
                                 session->bbtmp, AP_MODE_READBYTES,
                                 block? APR_BLOCK_READ : APR_NONBLOCK_READ,
-                                APR_BUCKET_BUFF_SIZE);
+                                H2MAX(APR_BUCKET_BUFF_SIZE, readlen));
         /* get rid of any possible data we do not expect to get */
         apr_brigade_cleanup(session->bbtmp); 
 
@@ -1523,16 +1585,25 @@ static apr_status_t h2_session_read(h2_session *session, int block)
                  * status. */
                 return rstatus;
         }
-        if ((session->io.bytes_read - read_start) > (64*1024)) {
+        if ((session->io.bytes_read - read_start) > readlen) {
             /* read enough in one go, give write a chance */
             ap_log_cerror(APLOG_MARK, APLOG_TRACE2, status, c,
-                          H2_SSSN_MSG(session, "read 64k, returning"));
+                          H2_SSSN_MSG(session, "read enough, returning"));
             break;
         }
     }
     return rstatus;
 }
 
+static apr_status_t h2_session_read(h2_session *session, int block)
+{
+    apr_status_t status = session_read(session, session->max_stream_mem
+                                       * H2MAX(2, session->open_streams), 
+                                       block);
+    h2_session_in_flush(session);
+    return status;
+}
+
 static const char *StateNames[] = {
     "INIT",      /* H2_SESSION_ST_INIT */
     "DONE",      /* H2_SESSION_ST_DONE */
@@ -1769,6 +1840,7 @@ static void h2_session_ev_pre_close(h2_session *session, int arg, const char *ms
 
 static void ev_stream_open(h2_session *session, h2_stream *stream)
 {
+    h2_iq_append(session->in_process, stream->id);
     switch (session->state) {
         case H2_SESSION_ST_IDLE:
             if (session->open_streams == 1) {
@@ -1779,14 +1851,6 @@ static void ev_stream_open(h2_session *session, h2_stream *stream)
         default:
             break;
     }
-    
-    ap_assert(!stream->scheduled);
-    if (h2_stream_prep_processing(stream) == APR_SUCCESS) {
-        h2_mplx_process(session->mplx, stream, stream_pri_cmp, session);
-    }
-    else {
-        h2_stream_rst(stream, H2_ERR_INTERNAL_ERROR);
-    }
 }
 
 static void ev_stream_closed(h2_session *session, h2_stream *stream)
@@ -1863,6 +1927,20 @@ static void on_stream_state_enter(void *ctx, h2_stream *stream)
     }
 }
 
+static void on_stream_event(void *ctx, h2_stream *stream, 
+                                  h2_stream_event_t ev)
+{
+    h2_session *session = ctx;
+    switch (ev) {
+        case H2_SEV_IN_DATA_PENDING:
+            h2_iq_append(session->in_pending, stream->id);
+            break;
+        default:
+            /* NOP */
+            break;
+    }
+}
+
 static void on_stream_state_event(void *ctx, h2_stream *stream, 
                                   h2_stream_event_t ev)
 {
diff --git a/modules/http2/h2_session.h b/modules/http2/h2_session.h
index fb3cd3d573..5751aed7bd 100644
--- a/modules/http2/h2_session.h
+++ b/modules/http2/h2_session.h
@@ -125,6 +125,10 @@ typedef struct h2_session {
     char status[64];                /* status message for scoreboard */
     int last_status_code;           /* the one already reported */
     const char *last_status_msg;    /* the one already reported */
+    
+    struct h2_iqueue *in_pending;   /* all streams with input pending */
+    struct h2_iqueue *in_process;   /* all streams ready for processing on slave */
+
 } h2_session;
 
 const char *h2_session_state_str(h2_session_state state);
@@ -155,6 +159,9 @@ apr_status_t h2_session_rcreate(h2_session **psession,
                                 request_rec *r, struct h2_ctx *ctx,
                                 struct h2_workers *workers);
 
+void h2_session_event(h2_session *session, h2_session_event_t ev, 
+                             int err, const char *msg);
+
 /**
  * Process the given HTTP/2 session until it is ended or a fatal
  * error occurred.
diff --git a/modules/http2/h2_stream.c b/modules/http2/h2_stream.c
index 71c38ca263..835bf238ff 100644
--- a/modules/http2/h2_stream.c
+++ b/modules/http2/h2_stream.c
@@ -157,9 +157,15 @@ static int on_frame_recv(h2_stream_state_t state, int frame_type)
     return on_frame(state, frame_type, trans_on_recv, H2_ALEN(trans_on_recv));
 }
 
-static int on_event(h2_stream_state_t state, h2_stream_event_t ev)
+static int on_event(h2_stream* stream, h2_stream_event_t ev)
 {
-    return on_map(state, trans_on_event[ev]);
+    if (stream->monitor && stream->monitor->on_event) {
+        stream->monitor->on_event(stream->monitor->ctx, stream, ev);
+    }
+    if (ev < H2_ALEN(trans_on_event)) {
+        return on_map(stream->state, trans_on_event[ev]);
+    }
+    return stream->state;
 }
 
 static void H2_STREAM_OUT_LOG(int lvl, h2_stream *s, const char *tag)
@@ -176,11 +182,16 @@ static void H2_STREAM_OUT_LOG(int lvl, h2_stream *s, const char *tag)
 }
 
 static apr_status_t setup_input(h2_stream *stream) {
-    if (stream->input == NULL && !stream->input_eof) {
-        h2_beam_create(&stream->input, stream->pool, stream->id, 
-                       "input", H2_BEAM_OWNER_SEND, 0, 
-                       stream->session->s->timeout);
-        h2_beam_send_from(stream->input, stream->pool);
+    if (stream->input == NULL) {
+        int empty = (stream->input_eof 
+                     && (!stream->in_buffer 
+                         || APR_BRIGADE_EMPTY(stream->in_buffer)));
+        if (!empty) {
+            h2_beam_create(&stream->input, stream->pool, stream->id, 
+                           "input", H2_BEAM_OWNER_SEND, 0, 
+                           stream->session->s->timeout);
+            h2_beam_send_from(stream->input, stream->pool);
+        }
     }
     return APR_SUCCESS;
 }
@@ -202,27 +213,27 @@ static apr_status_t close_input(h2_stream *stream)
     }
     
     if (stream->trailers && !apr_is_empty_table(stream->trailers)) {
-        apr_bucket_brigade *tmp;
         apr_bucket *b;
         h2_headers *r;
         
-        tmp = apr_brigade_create(stream->pool, c->bucket_alloc);
+        if (!stream->in_buffer) {
+            stream->in_buffer = apr_brigade_create(stream->pool, c->bucket_alloc);
+        }
         
         r = h2_headers_create(HTTP_OK, stream->trailers, NULL, stream->pool);
         stream->trailers = NULL;        
         b = h2_bucket_headers_create(c->bucket_alloc, r);
-        APR_BRIGADE_INSERT_TAIL(tmp, b);
+        APR_BRIGADE_INSERT_TAIL(stream->in_buffer, b);
         
         b = apr_bucket_eos_create(c->bucket_alloc);
-        APR_BRIGADE_INSERT_TAIL(tmp, b);
+        APR_BRIGADE_INSERT_TAIL(stream->in_buffer, b);
         
         ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, stream->session->c,
                       H2_STRM_MSG(stream, "added trailers"));
-        setup_input(stream);
-        status = h2_beam_send(stream->input, tmp, APR_BLOCK_READ);
-        apr_brigade_destroy(tmp);
+        h2_stream_dispatch(stream, H2_SEV_IN_DATA_PENDING);
     }
     if (stream->input) {
+        h2_stream_flush_input(stream);
         return h2_beam_close(stream->input);
     }
     return status;
@@ -329,7 +340,7 @@ void h2_stream_dispatch(h2_stream *stream, h2_stream_event_t ev)
     
     ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, stream->session->c,
                   H2_STRM_MSG(stream, "dispatch event %d"), ev);
-    new_state = on_event(stream->state, ev);
+    new_state = on_event(stream, ev);
     if (new_state < 0) {
         ap_log_cerror(APLOG_MARK, APLOG_WARNING, 0, stream->session->c, 
                       H2_STRM_LOG(APLOGNO(10002), stream, "invalid event %d"), ev);
@@ -340,7 +351,7 @@ void h2_stream_dispatch(h2_stream *stream, h2_stream_event_t ev)
     else if (new_state == stream->state) {
         /* nop */
         ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, stream->session->c,
-                      H2_STRM_MSG(stream, "ignored event %d"), ev);
+                      H2_STRM_MSG(stream, "non-state event %d"), ev);
         return;
     }
     else {
@@ -399,7 +410,7 @@ apr_status_t h2_stream_send_frame(h2_stream *stream, int ftype, int flags)
                   H2_STRM_MSG(stream, "send frame %d, eos=%d"), ftype, eos);
     status = transit(stream, new_state);
     if (status == APR_SUCCESS && eos) {
-        status = transit(stream, on_event(stream->state, H2_SEV_CLOSED_L));
+        status = transit(stream, on_event(stream, H2_SEV_CLOSED_L));
     }
     return status;
 }
@@ -449,7 +460,23 @@ apr_status_t h2_stream_recv_frame(h2_stream *stream, int ftype, int flags)
     }
     status = transit(stream, new_state);
     if (status == APR_SUCCESS && eos) {
-        status = transit(stream, on_event(stream->state, H2_SEV_CLOSED_R));
+        status = transit(stream, on_event(stream, H2_SEV_CLOSED_R));
+    }
+    return status;
+}
+
+apr_status_t h2_stream_flush_input(h2_stream *stream)
+{
+    apr_status_t status = APR_SUCCESS;
+    
+    if (stream->in_buffer && !APR_BRIGADE_EMPTY(stream->in_buffer)) {
+        setup_input(stream);
+        status = h2_beam_send(stream->input, stream->in_buffer, APR_BLOCK_READ);
+        stream->in_last_write = apr_time_now();
+    }
+    if (stream->input_eof 
+        && stream->input && !h2_beam_is_closed(stream->input)) {
+        status = h2_beam_close(stream->input);
     }
     return status;
 }
@@ -459,21 +486,27 @@ apr_status_t h2_stream_recv_DATA(h2_stream *stream, uint8_t flags,
 {
     h2_session *session = stream->session;
     apr_status_t status = APR_SUCCESS;
-    apr_bucket_brigade *tmp;
     
-    ap_assert(stream);
-    if (len > 0) {
-        ap_log_cerror(APLOG_MARK, APLOG_TRACE2, status, session->c,
-                      H2_STRM_MSG(stream, "recv DATA, len=%d"), (int)len);
-        
-        tmp = apr_brigade_create(stream->pool, session->c->bucket_alloc);
-        apr_brigade_write(tmp, NULL, NULL, (const char *)data, len);
-        setup_input(stream);
-        status = h2_beam_send(stream->input, tmp, APR_BLOCK_READ);
-        apr_brigade_destroy(tmp);
-    }
     stream->in_data_frames++;
-    stream->in_data_octets += len;
+    if (len > 0) {
+        if (APLOGctrace3(session->c)) {
+            const char *load = apr_pstrndup(stream->pool, (const char *)data, len);
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE3, 0, session->c,
+                          H2_STRM_MSG(stream, "recv DATA, len=%d: -->%s<--"), 
+                          (int)len, load);
+        }
+        else {
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE2, status, session->c,
+                          H2_STRM_MSG(stream, "recv DATA, len=%d"), (int)len);
+        }
+        stream->in_data_octets += len;
+        if (!stream->in_buffer) {
+            stream->in_buffer = apr_brigade_create(stream->pool, 
+                                                   session->c->bucket_alloc);
+        }
+        apr_brigade_write(stream->in_buffer, NULL, NULL, (const char *)data, len);
+        h2_stream_dispatch(stream, H2_SEV_IN_DATA_PENDING);
+    }
     return status;
 }
 
@@ -500,7 +533,11 @@ h2_stream *h2_stream_create(int id, apr_pool_t *pool, h2_session *session,
     
     h2_beam_create(&stream->output, pool, id, "output", H2_BEAM_OWNER_RECV, 0,
                    session->s->timeout);
-    
+                   
+    stream->in_window_size = 
+        nghttp2_session_get_stream_local_window_size(
+            stream->session->ngh2, stream->id);
+
     ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, session->c, 
                   H2_STRM_LOG(APLOGNO(03082), stream, "created"));
     on_state_enter(stream);
diff --git a/modules/http2/h2_stream.h b/modules/http2/h2_stream.h
index bbb2dc7677..15d4399540 100644
--- a/modules/http2/h2_stream.h
+++ b/modules/http2/h2_stream.h
@@ -57,6 +57,8 @@ typedef struct h2_stream_monitor {
                                              was detected */
     h2_stream_event_cb *on_state_event;   /* called right before the given event
                                              result in a new stream state */
+    h2_stream_event_cb *on_event;         /* called for events that do not 
+                                             trigger a state change */
 } h2_stream_monitor;
 
 struct h2_stream {
@@ -74,9 +76,13 @@ struct h2_stream {
     int request_headers_added;  /* number of request headers added */
     
     struct h2_bucket_beam *input;
+    apr_bucket_brigade *in_buffer;
+    int in_window_size;
+    apr_time_t in_last_write;
+    
     struct h2_bucket_beam *output;
-    apr_size_t max_mem;         /* maximum amount of data buffered */
     apr_bucket_brigade *out_buffer;
+    apr_size_t max_mem;         /* maximum amount of data buffered */
 
     int rst_error;              /* stream error for RST_STREAM */
     unsigned int aborted   : 1; /* was aborted */
@@ -205,6 +211,8 @@ apr_status_t h2_stream_recv_frame(h2_stream *stream, int frame_type, int flags);
 apr_status_t h2_stream_recv_DATA(h2_stream *stream, uint8_t flags,
                                  const uint8_t *data, size_t len);
 
+apr_status_t h2_stream_flush_input(h2_stream *stream);
+
 /**
  * Reset the stream. Stream write/reads will return errors afterwards.
  *
@@ -291,7 +299,6 @@ const char *h2_stream_state_str(h2_stream *stream);
  */
 int h2_stream_is_ready(h2_stream *stream);
 
-
 #define H2_STRM_MSG(s, msg)     \
     "h2_stream(%ld-%d,%s): "msg, s->session->id, s->id, h2_stream_state_str(s)
 
diff --git a/modules/http2/h2_task.c b/modules/http2/h2_task.c
index 8e668b8c4f..a93fce4cd2 100644
--- a/modules/http2/h2_task.c
+++ b/modules/http2/h2_task.c
@@ -216,14 +216,18 @@ static apr_status_t h2_filter_slave_in(ap_filter_t* f,
     apr_status_t status = APR_SUCCESS;
     apr_bucket *b, *next;
     apr_off_t bblen;
-    apr_size_t rmax;
+    const int trace1 = APLOGctrace1(f->c);
+    apr_size_t rmax = ((readbytes <= APR_SIZE_MAX)? 
+                       (apr_size_t)readbytes : APR_SIZE_MAX);
     
     task = h2_ctx_cget_task(f->c);
     ap_assert(task);
-    rmax = ((readbytes <= APR_SIZE_MAX)? (apr_size_t)readbytes : APR_SIZE_MAX);
-    ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, f->c,
-                  "h2_slave_in(%s): read, mode=%d, block=%d, readbytes=%ld", 
-                  task->id, mode, block, (long)readbytes);
+
+    if (trace1) {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, f->c,
+                      "h2_slave_in(%s): read, mode=%d, block=%d, readbytes=%ld", 
+                      task->id, mode, block, (long)readbytes);
+    }
     
     if (mode == AP_MODE_INIT) {
         return ap_get_brigade(f->c->input_filters, bb, mode, block, readbytes);
@@ -249,19 +253,23 @@ static apr_status_t h2_filter_slave_in(ap_filter_t* f,
     
     while (APR_BRIGADE_EMPTY(task->input.bb)) {
         /* Get more input data for our request. */
-        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, status, f->c,
-                      "h2_slave_in(%s): get more data from mplx, block=%d, "
-                      "readbytes=%ld", task->id, block, (long)readbytes);
+        if (trace1) {
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE1, status, f->c,
+                          "h2_slave_in(%s): get more data from mplx, block=%d, "
+                          "readbytes=%ld", task->id, block, (long)readbytes);
+        }
         if (task->input.beam) {
             status = h2_beam_receive(task->input.beam, task->input.bb, block, 
-                                     H2MIN(readbytes, 32*1024));
+                                     128*1024);
         }
         else {
             status = APR_EOF;
         }
         
-        ap_log_cerror(APLOG_MARK, APLOG_TRACE2, status, f->c,
-                      "h2_slave_in(%s): read returned", task->id);
+        if (trace1) {
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE2, status, f->c,
+                          "h2_slave_in(%s): read returned", task->id);
+        }
         if (APR_STATUS_IS_EAGAIN(status) 
             && (mode == AP_MODE_GETLINE || block == APR_BLOCK_READ)) {
             /* chunked input handling does not seem to like it if we
@@ -275,9 +283,11 @@ static apr_status_t h2_filter_slave_in(ap_filter_t* f,
         else if (status != APR_SUCCESS) {
             return status;
         }
-        
-        h2_util_bb_log(f->c, task->stream_id, APLOG_TRACE2, 
-                       "input.beam recv raw", task->input.bb);
+
+        if (trace1) {
+            h2_util_bb_log(f->c, task->stream_id, APLOG_TRACE2, 
+                        "input.beam recv raw", task->input.bb);
+        }
         if (h2_task_logio_add_bytes_in) {
             apr_brigade_length(bb, 0, &bblen);
             h2_task_logio_add_bytes_in(f->c, bblen);
@@ -291,12 +301,16 @@ static apr_status_t h2_filter_slave_in(ap_filter_t* f,
         return (mode == AP_MODE_SPECULATIVE)? APR_EAGAIN : APR_EOF;
     }
 
-    h2_util_bb_log(f->c, task->stream_id, APLOG_TRACE2, 
-                   "task_input.bb", task->input.bb);
+    if (trace1) {
+        h2_util_bb_log(f->c, task->stream_id, APLOG_TRACE2, 
+                    "task_input.bb", task->input.bb);
+    }
            
     if (APR_BRIGADE_EMPTY(task->input.bb)) {
-        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, f->c,
-                      "h2_slave_in(%s): no data", task->id);
+        if (trace1) {
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, f->c,
+                          "h2_slave_in(%s): no data", task->id);
+        }
         return (block == APR_NONBLOCK_READ)? APR_EAGAIN : APR_EOF;
     }
     
@@ -321,9 +335,11 @@ static apr_status_t h2_filter_slave_in(ap_filter_t* f,
             apr_size_t len = sizeof(buffer)-1;
             apr_brigade_flatten(bb, buffer, &len);
             buffer[len] = 0;
-            ap_log_cerror(APLOG_MARK, APLOG_TRACE1, status, f->c,
-                          "h2_slave_in(%s): getline: %s",
-                          task->id, buffer);
+            if (trace1) {
+                ap_log_cerror(APLOG_MARK, APLOG_TRACE1, status, f->c,
+                              "h2_slave_in(%s): getline: %s",
+                              task->id, buffer);
+            }
         }
     }
     else {
@@ -336,7 +352,7 @@ static apr_status_t h2_filter_slave_in(ap_filter_t* f,
         status = APR_ENOTIMPL;
     }
     
-    if (APLOGctrace1(f->c)) {
+    if (trace1) {
         apr_brigade_length(bb, 0, &bblen);
         ap_log_cerror(APLOG_MARK, APLOG_TRACE1, status, f->c,
                       "h2_slave_in(%s): %ld data bytes", task->id, (long)bblen);
diff --git a/modules/http2/h2_util.c b/modules/http2/h2_util.c
index 0bd74dc28e..4f4616e5c5 100644
--- a/modules/http2/h2_util.c
+++ b/modules/http2/h2_util.c
@@ -991,17 +991,16 @@ apr_status_t h2_brigade_concat_length(apr_bucket_brigade *dest,
                                       apr_bucket_brigade *src,
                                       apr_off_t length)
 {
-    apr_bucket *b, *next;
+    apr_bucket *b;
     apr_off_t remain = length;
     apr_status_t status = APR_SUCCESS;
     
-    for (b = APR_BRIGADE_FIRST(src); 
-         b != APR_BRIGADE_SENTINEL(src);
-         b = next) {
-        next = APR_BUCKET_NEXT(b);
+    while (!APR_BRIGADE_EMPTY(src)) {
+        b = APR_BRIGADE_FIRST(src); 
         
         if (APR_BUCKET_IS_METADATA(b)) {
-            /* fall through */
+            APR_BUCKET_REMOVE(b);
+            APR_BRIGADE_INSERT_TAIL(dest, b);
         }
         else {
             if (remain == b->length) {
@@ -1024,10 +1023,10 @@ apr_status_t h2_brigade_concat_length(apr_bucket_brigade *dest,
                     apr_bucket_split(b, remain);
                 }
             }
+            APR_BUCKET_REMOVE(b);
+            APR_BRIGADE_INSERT_TAIL(dest, b);
+            remain -= b->length;
         }
-        APR_BUCKET_REMOVE(b);
-        APR_BRIGADE_INSERT_TAIL(dest, b);
-        remain -= b->length;
     }
     return status;
 }
@@ -1215,55 +1214,14 @@ apr_size_t h2_util_bucket_print(char *buffer, apr_size_t bmax,
     if (bmax <= off) {
         return off;
     }
-    if (APR_BUCKET_IS_METADATA(b)) {
-        if (APR_BUCKET_IS_EOS(b)) {
-            off += apr_snprintf(buffer+off, bmax-off, "eos");
-        }
-        else if (APR_BUCKET_IS_FLUSH(b)) {
-            off += apr_snprintf(buffer+off, bmax-off, "flush");
-        }
-        else if (AP_BUCKET_IS_EOR(b)) {
-            off += apr_snprintf(buffer+off, bmax-off, "eor");
-        }
-        else {
-            off += apr_snprintf(buffer+off, bmax-off, "%s", b->type->name);
-        }
+    else if (APR_BUCKET_IS_METADATA(b)) {
+        off += apr_snprintf(buffer+off, bmax-off, "%s", b->type->name);
     }
-    else {
-        const char *btype = b->type->name;
-        if (APR_BUCKET_IS_FILE(b)) {
-            btype = "file";
-        }
-        else if (APR_BUCKET_IS_PIPE(b)) {
-            btype = "pipe";
-        }
-        else if (APR_BUCKET_IS_SOCKET(b)) {
-            btype = "socket";
-        }
-        else if (APR_BUCKET_IS_HEAP(b)) {
-            btype = "heap";
-        }
-        else if (APR_BUCKET_IS_TRANSIENT(b)) {
-            btype = "transient";
-        }
-        else if (APR_BUCKET_IS_IMMORTAL(b)) {
-            btype = "immortal";
-        }
-#if APR_HAS_MMAP
-        else if (APR_BUCKET_IS_MMAP(b)) {
-            btype = "mmap";
-        }
-#endif
-        else if (APR_BUCKET_IS_POOL(b)) {
-            btype = "pool";
-        }
-        
-        if (bmax > off) {
-            off += apr_snprintf(buffer+off, bmax-off, "%s[%ld]", 
-                                btype, 
-                                (long)(b->length == ((apr_size_t)-1)? 
-                                       -1 : b->length));
-        }
+    else if (bmax > off) {
+        off += apr_snprintf(buffer+off, bmax-off, "%s[%ld]", 
+                            b->type->name, 
+                            (long)(b->length == ((apr_size_t)-1)? 
+                                   -1 : b->length));
     }
     return off;
 }
diff --git a/modules/http2/h2_util.h b/modules/http2/h2_util.h
index 503a8329bf..f6a4b9a43d 100644
--- a/modules/http2/h2_util.h
+++ b/modules/http2/h2_util.h
@@ -430,8 +430,8 @@ do { \
     const char *line = "(null)"; \
     apr_size_t len, bmax = sizeof(buffer)/sizeof(buffer[0]); \
     len = h2_util_bb_print(buffer, bmax, (tag), "", (bb)); \
-    ap_log_cerror(APLOG_MARK, level, 0, (c), "bb_dump(%s): %s", \
-        (c)->log_id, (len? buffer : line)); \
+    ap_log_cerror(APLOG_MARK, level, 0, (c), "bb_dump(%ld): %s", \
+        ((c)->master? (c)->master->id : (c)->id), (len? buffer : line)); \
 } while(0)