Mark Kirkwood wrote:
Kris Kennaway wrote:
If so, then your task is the following:
Make SYSV semaphores less dumb about process wakeups. Currently
whenever the semaphore state changes, all processes sleeping on the
semaphore are woken, even if we only have released enough resources
for one
Mark Kirkwood wrote:
Kris Kennaway wrote:
If so, then your task is the following:
Make SYSV semaphores less dumb about process wakeups. Currently
whenever the semaphore state changes, all processes sleeping on the
semaphore are woken, even if we only have released enough resources
for one
Kris Kennaway wrote:
If so, then your task is the following:
Make SYSV semaphores less dumb about process wakeups. Currently
whenever the semaphore state changes, all processes sleeping on the
semaphore are woken, even if we only have released enough resources
for one waiting process to claim.
Mark Kirkwood [EMAIL PROTECTED] writes:
Kris Kennaway wrote:
If so, then your task is the following:
Make SYSV semaphores less dumb about process wakeups. Currently
whenever the semaphore state changes, all processes sleeping on the
semaphore are woken, even if we only have released enough
Kris Kennaway [EMAIL PROTECTED] writes:
Make SYSV semaphores less dumb about process wakeups. Currently
whenever the semaphore state changes, all processes sleeping on the
semaphore are woken, even if we only have released enough resources
for one waiting process to claim.
Correct. The
On Tue, Apr 10, 2007 at 10:41:04PM +1200, Mark Kirkwood wrote:
Kris Kennaway wrote:
If so, then your task is the following:
Make SYSV semaphores less dumb about process wakeups. Currently
whenever the semaphore state changes, all processes sleeping on the
semaphore are woken, even if we
On Tue, Apr 10, 2007 at 10:23:42AM -0400, Tom Lane wrote:
Mark Kirkwood [EMAIL PROTECTED] writes:
Kris Kennaway wrote:
If so, then your task is the following:
Make SYSV semaphores less dumb about process wakeups. Currently
whenever the semaphore state changes, all processes sleeping
Kris Kennaway [EMAIL PROTECTED] writes:
On Tue, Apr 10, 2007 at 02:46:56PM -0400, Tom Lane wrote:
Oh, I'm sure the BSD kernel acts as you describe. But Mark's point is
that Postgres never has more than one process waiting on any particular
SysV semaphore, and so the problem doesn't really
Kris Kennaway [EMAIL PROTECTED] writes:
I have not studied the exact code path, but there are indeed multiple
wakeups happening from the semaphore code (as many as the number of
active postgresql processes). It is easy to instrument
sleepq_broadcast() and log them when they happen.
There are
On 2007-04-10, Tom Lane [EMAIL PROTECTED] wrote:
Kris Kennaway [EMAIL PROTECTED] writes:
I have not studied the exact code path, but there are indeed multiple
wakeups happening from the semaphore code (as many as the number of
active postgresql processes). It is easy to instrument
Kris Kennaway [EMAIL PROTECTED] writes:
On Tue, Apr 10, 2007 at 05:36:17PM -0400, Tom Lane wrote:
Anyway I'd be interested to know what the test case is, and which PG
version you were testing.
I used 8.2 (and some older version when I first noticed it a year ago)
and either sysbench or
On Tue, Apr 10, 2007 at 03:52:00PM -0400, Tom Lane wrote:
Kris Kennaway [EMAIL PROTECTED] writes:
On Tue, Apr 10, 2007 at 02:46:56PM -0400, Tom Lane wrote:
Oh, I'm sure the BSD kernel acts as you describe. But Mark's point is
that Postgres never has more than one process waiting on any
On Tue, Apr 10, 2007 at 06:26:37PM -0400, Tom Lane wrote:
Kris Kennaway [EMAIL PROTECTED] writes:
On Tue, Apr 10, 2007 at 05:36:17PM -0400, Tom Lane wrote:
Anyway I'd be interested to know what the test case is, and which PG
version you were testing.
I used 8.2 (and some older version
On Tue, Apr 10, 2007 at 02:46:56PM -0400, Tom Lane wrote:
Kris Kennaway [EMAIL PROTECTED] writes:
Make SYSV semaphores less dumb about process wakeups. Currently
whenever the semaphore state changes, all processes sleeping on the
semaphore are woken, even if we only have released enough
On Tue, Apr 10, 2007 at 05:36:17PM -0400, Tom Lane wrote:
Kris Kennaway [EMAIL PROTECTED] writes:
I have not studied the exact code path, but there are indeed multiple
wakeups happening from the semaphore code (as many as the number of
active postgresql processes). It is easy to instrument
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