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Prevent lwlock dtrace probes from unnecessary work

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If dtrace is compiled in but disabled, the lwlock dtrace probes still
evaluate their arguments.  Since PostgreSQL 13, T_NAME(lock) does
nontrivial work, so it should be avoided if not needed.  To fix, make
these calls conditional on the *_ENABLED() macro corresponding to each
probe.

Reviewed-by: Craig Ringer <craig.ringer@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/CAGRY4nwxKUS_RvXFW-ugrZBYxPFFM5kjwKT5O+0+Stuga5b4+Q@mail.gmail.com
This commit is contained in:
Peter Eisentraut
2021-05-03 12:11:33 +02:00
parent 3eeadc425c
commit e48ce7ef0e
1 changed files with 26 additions and 13 deletions
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13
src/backend/storage/lmgr/lwlock.c
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@ -1323,6 +1323,7 @@ LWLockAcquire(LWLock *lock, LWLockMode mode)
#endif #endif
LWLockReportWaitStart(lock); LWLockReportWaitStart(lock);
if (TRACE_POSTGRESQL_LWLOCK_WAIT_START_ENABLED())
TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode);
for (;;) for (;;)
@ -1345,6 +1346,7 @@ LWLockAcquire(LWLock *lock, LWLockMode mode)
} }
#endif #endif
if (TRACE_POSTGRESQL_LWLOCK_WAIT_DONE_ENABLED())
TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), mode);
LWLockReportWaitEnd(); LWLockReportWaitEnd();
@ -1354,6 +1356,7 @@ LWLockAcquire(LWLock *lock, LWLockMode mode)
result = false; result = false;
} }
if (TRACE_POSTGRESQL_LWLOCK_ACQUIRE_ENABLED())
TRACE_POSTGRESQL_LWLOCK_ACQUIRE(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_ACQUIRE(T_NAME(lock), mode);
/* Add lock to list of locks held by this backend */ /* Add lock to list of locks held by this backend */
@ -1405,6 +1408,7 @@ LWLockConditionalAcquire(LWLock *lock, LWLockMode mode)
RESUME_INTERRUPTS(); RESUME_INTERRUPTS();
LOG_LWDEBUG("LWLockConditionalAcquire", lock, "failed"); LOG_LWDEBUG("LWLockConditionalAcquire", lock, "failed");
if (TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE_FAIL_ENABLED())
TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE_FAIL(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE_FAIL(T_NAME(lock), mode);
} }
else else
@ -1412,6 +1416,7 @@ LWLockConditionalAcquire(LWLock *lock, LWLockMode mode)
/* Add lock to list of locks held by this backend */ /* Add lock to list of locks held by this backend */
held_lwlocks[num_held_lwlocks].lock = lock; held_lwlocks[num_held_lwlocks].lock = lock;
held_lwlocks[num_held_lwlocks++].mode = mode; held_lwlocks[num_held_lwlocks++].mode = mode;
if (TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE_ENABLED())
TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE(T_NAME(lock), mode);
} }
return !mustwait; return !mustwait;
@ -1484,6 +1489,7 @@ LWLockAcquireOrWait(LWLock *lock, LWLockMode mode)
#endif #endif
LWLockReportWaitStart(lock); LWLockReportWaitStart(lock);
if (TRACE_POSTGRESQL_LWLOCK_WAIT_START_ENABLED())
TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode);
for (;;) for (;;)
@ -1502,6 +1508,7 @@ LWLockAcquireOrWait(LWLock *lock, LWLockMode mode)
Assert(nwaiters < MAX_BACKENDS); Assert(nwaiters < MAX_BACKENDS);
} }
#endif #endif
if (TRACE_POSTGRESQL_LWLOCK_WAIT_DONE_ENABLED())
TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), mode);
LWLockReportWaitEnd(); LWLockReportWaitEnd();
@ -1532,6 +1539,7 @@ LWLockAcquireOrWait(LWLock *lock, LWLockMode mode)
/* Failed to get lock, so release interrupt holdoff */ /* Failed to get lock, so release interrupt holdoff */
RESUME_INTERRUPTS(); RESUME_INTERRUPTS();
LOG_LWDEBUG("LWLockAcquireOrWait", lock, "failed"); LOG_LWDEBUG("LWLockAcquireOrWait", lock, "failed");
if (TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT_FAIL_ENABLED())
TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT_FAIL(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT_FAIL(T_NAME(lock), mode);
} }
else else
@ -1540,6 +1548,7 @@ LWLockAcquireOrWait(LWLock *lock, LWLockMode mode)
/* Add lock to list of locks held by this backend */ /* Add lock to list of locks held by this backend */
held_lwlocks[num_held_lwlocks].lock = lock; held_lwlocks[num_held_lwlocks].lock = lock;
held_lwlocks[num_held_lwlocks++].mode = mode; held_lwlocks[num_held_lwlocks++].mode = mode;
if (TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT_ENABLED())
TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT(T_NAME(lock), mode); TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT(T_NAME(lock), mode);
} }
@ -1700,6 +1709,7 @@ LWLockWaitForVar(LWLock *lock, uint64 *valptr, uint64 oldval, uint64 *newval)
#endif #endif
LWLockReportWaitStart(lock); LWLockReportWaitStart(lock);
if (TRACE_POSTGRESQL_LWLOCK_WAIT_START_ENABLED())
TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), LW_EXCLUSIVE); TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), LW_EXCLUSIVE);
for (;;) for (;;)
@ -1719,6 +1729,7 @@ LWLockWaitForVar(LWLock *lock, uint64 *valptr, uint64 oldval, uint64 *newval)
} }
#endif #endif
if (TRACE_POSTGRESQL_LWLOCK_WAIT_DONE_ENABLED())
TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), LW_EXCLUSIVE); TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), LW_EXCLUSIVE);
LWLockReportWaitEnd(); LWLockReportWaitEnd();
@ -1727,6 +1738,7 @@ LWLockWaitForVar(LWLock *lock, uint64 *valptr, uint64 oldval, uint64 *newval)
/* Now loop back and check the status of the lock again. */ /* Now loop back and check the status of the lock again. */
} }
if (TRACE_POSTGRESQL_LWLOCK_ACQUIRE_ENABLED())
TRACE_POSTGRESQL_LWLOCK_ACQUIRE(T_NAME(lock), LW_EXCLUSIVE); TRACE_POSTGRESQL_LWLOCK_ACQUIRE(T_NAME(lock), LW_EXCLUSIVE);
/* /*
@ -1870,6 +1882,7 @@ LWLockRelease(LWLock *lock)
LWLockWakeup(lock); LWLockWakeup(lock);
} }
if (TRACE_POSTGRESQL_LWLOCK_RELEASE_ENABLED())
TRACE_POSTGRESQL_LWLOCK_RELEASE(T_NAME(lock)); TRACE_POSTGRESQL_LWLOCK_RELEASE(T_NAME(lock));
/* /*