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An alternative messaging strategy for the OPFS VFS proxy which uses only SharedArrayBuffer and Atomics, instead of worker messages, for communication (only the initial one-time handshake during initialization uses worker messages). It runs speedtest1 approx. 15-20% faster but still 20-ish% slower than WASMFS.

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FossilOrigin-Name: a83ee3082d89439ea3ad5737e63e25bebb0f91895aca006ce5fecf5b93a2651a
This commit is contained in:
stephan
2022-09-20 08:27:57 +00:00
parent 138647a552
commit 5e8bb0aa13
6 changed files with 200 additions and 145 deletions
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60
ext/wasm/api/sqlite3-api-opfs.js
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@ -128,7 +128,6 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
// failure is, e.g., that the remote script is 404.
promiseReject(new Error("Loading OPFS async Worker failed for unknown reasons."));
};
const wMsg = (type,args)=>W.postMessage({type,args});
/**
Generic utilities for working with OPFS. This will get filled out
by the Promise setup and, on success, installed as sqlite3.opfs.
@ -203,7 +202,6 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
{
let i = 0;
state.opIds.whichOp = i++;
state.opIds.nothing = i++;
state.opIds.xAccess = i++;
state.rcIds.xAccess = i++;
state.opIds.xClose = i++;
@ -228,8 +226,9 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
state.rcIds.xWrite = i++;
state.opIds.mkdir = i++;
state.rcIds.mkdir = i++;
state.opIds.xFileControl = i++;
state.rcIds.xFileControl = i++;
state.sabOP = new SharedArrayBuffer(i * 4/*sizeof int32*/);
state.opIds.xFileControl = state.opIds.xSync /* special case */;
opfsUtil.metrics.reset();
}
@ -260,12 +259,17 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
given operation's signature in the async API counterpart.
*/
const opRun = (op,...args)=>{
const rcNdx = state.rcIds[op] || toss("Invalid rc ID:",op);
const opNdx = state.opIds[op] || toss("Invalid op ID:",op);
state.s11n.serialize(...args);
Atomics.store(state.sabOPView, rcNdx, -1);
Atomics.store(state.sabOPView, state.opIds.whichOp, opNdx);
Atomics.notify(state.sabOPView, state.opIds.whichOp) /* async thread will take over here */;
const t = performance.now();
Atomics.store(state.sabOPView, state.opIds[op], -1);
wMsg(op, args);
Atomics.wait(state.sabOPView, state.opIds[op], -1);
Atomics.wait(state.sabOPView, rcNdx, -1);
const rc = Atomics.load(state.sabOPView, rcNdx);
metrics[op].wait += performance.now() - t;
return Atomics.load(state.sabOPView, state.opIds[op]);
return rc;
};
const initS11n = ()=>{
@ -297,11 +301,25 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
serialization for simplicy of implementation, but if that
proves imperformant then a lower-level approach will be
created.
If passed "too much data" (more that the shared buffer size
it will either throw or truncate the data (not certain
which)). This routine is only intended for serializing OPFS
VFS arguments and (in at least one special case) result
values, and the buffer is sized to be able to comfortably
handle those.
If passed no arguments then it zeroes out the serialization
state.
*/
state.s11n.serialize = function(...args){
const json = jsonEncoder.encode(JSON.stringify(args));
viewSz.setInt32(0, json.byteLength, state.littleEndian);
viewJson.set(json);
if(args.length){
const json = jsonEncoder.encode(JSON.stringify(args));
viewSz.setInt32(0, json.byteLength, state.littleEndian);
viewJson.set(json);
}else{
viewSz.setInt32(0, 0, state.littleEndian);
}
};
return state.s11n;
};
@ -552,9 +570,8 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
const vfsSyncWrappers = {
xAccess: function(pVfs,zName,flags,pOut){
mTimeStart('xAccess');
wasm.setMemValue(
pOut, (opRun('xAccess', wasm.cstringToJs(zName)) ? 0 : 1), 'i32'
);
const rc = opRun('xAccess', wasm.cstringToJs(zName));
wasm.setMemValue( pOut, (rc ? 0 : 1), 'i32' );
mTimeEnd();
return 0;
},
@ -686,22 +703,12 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
opfsUtil.deleteEntry = function(fsEntryName,recursive=false){
return 0===opRun('xDelete', fsEntryName, 0, recursive);
};
/**
Exactly like deleteEntry() but runs asynchronously. This is a
"fire and forget" operation: it does not return a promise
because the counterpart operation happens in another thread and
waiting on that result in a Promise would block the OPFS VFS
from acting until it completed.
*/
opfsUtil.deleteEntryAsync = function(fsEntryName,recursive=false){
wMsg('xDeleteNoWait', [fsEntryName, 0, recursive]);
};
/**
Synchronously creates the given directory name, recursively, in
the OPFS filesystem. Returns true if it succeeds or the
directory already exists, else false.
*/
opfsUtil.mkdir = async function(absDirName){
opfsUtil.mkdir = function(absDirName){
return 0===opRun('mkdir', absDirName);
};
/**
@ -736,7 +743,7 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
features like getting a directory listing.
*/
const sanityCheck = async function(){
const sanityCheck = function(){
const scope = wasm.scopedAllocPush();
const sq3File = new sqlite3_file();
try{
@ -791,6 +798,7 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
vfsSyncWrappers.xAccess(opfsVfs.pointer, zDbFile, 0, pOut);
rc = wasm.getMemValue(pOut,'i32');
if(rc) toss("Expecting 0 from xAccess(",dbFile,") after xDelete().");
log("End of OPFS sanity checks.");
}finally{
sq3File.dispose();
wasm.scopedAllocPop(scope);
@ -803,7 +811,7 @@ sqlite3.installOpfsVfs = function callee(asyncProxyUri = callee.defaultProxyUri)
switch(data.type){
case 'opfs-async-loaded':
/*Pass our config and shared state on to the async worker.*/
wMsg('opfs-async-init',state);
W.postMessage({type: 'opfs-async-init',args: state});
break;
case 'opfs-async-inited':{
/*Indicates that the async partner has received the 'init',