Date: Sun, 25 Feb 2007 19:22:35 -0500 From: Kris Kennaway <kris@obsecurity.org> To: current@FreeBSD.org Cc: performance@FreeBSD.org Subject: Anyone interested in improving postgresql scaling? Message-ID: <20070226002234.GA80974@xor.obsecurity.org>
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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. i.e. there is a thundering herd wakeup situation which destroys performance at high loads. Fixing this will involve replacing the wakeup() calls with appropriate amounts of wakeup_one(). Kris
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