cvs commit: src/sys/kern sysv_sem.c

Colin Percival colin.percival at
Wed Mar 24 10:40:56 PST 2004

At 17:51 24/03/2004, Sean Chittenden wrote:
>>  FreeBSD src repository
>>  Modified files:
>>    sys/kern             sysv_sem.c
>>  Log:
>>  Adjust the number of processes waiting on a semaphore properly if we're
>>  woken up in the middle of sleeping.
>Have you read the thread on performance@ regarding semaphore performance problems for PostgreSQL?  Do you think this has any bearing on that problem?  -sc

I hadn't seen the thread on performance@ until now, but it sounds like this
is very likely related -- this bug would result in processes not being woken
up when a semaphore becomes free.

Jason, could you update your src/sys/kern/sysv_sem.c to the latest revision
(1.69), build a new kernel, and see if the problem goes away?

Colin Percival

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