From: Steinar H. Gunderson <sgunderson@bigfoot.com>
To: pgsql-performance@postgresql.org
Subject: Re: Hardware/OS recommendations for large databases (
Date: Sun, 20 Nov 2005 15:29:35 +0100
Message-ID: <20051120142935.GA32311@uio.no> (raw)
In-Reply-To: <87y83jo0um.fsf@stark.xeocode.com>
References: <BFA48F15.14182%llonergan@greenplum.com>
<437FE2E4.5040600@rentec.com>
<87y83jo0um.fsf@stark.xeocode.com>
On Sun, Nov 20, 2005 at 09:22:41AM -0500, Greg Stark wrote:
> I don't think that's true. If the syscall was preemptable then it wouldn't
> show up under "iowait", but rather "idle". The time spent in iowait is time in
> uninterruptable sleeps where no other process can be scheduled.
You are confusing userspace with kernel space. When a process is stuck in
uninterruptable sleep, it means _that process_ can't be interrupted (say,
by a signal). The kernel can preempt it without problems.
/* Steinar */
--
Homepage: http://www.sesse.net/
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To: pgsql-performance@postgresql.org
Cc: sgunderson@bigfoot.com
Subject: Re: Hardware/OS recommendations for large databases (
In-Reply-To: <20051120142935.GA32311@uio.no>
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