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Re: spinlocks on HP-UX

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: spinlocks on HP-UX
Date: 2011-08-30 22:33:49
Message-ID: 28773.1314743629@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Aug 30, 2011 at 4:37 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> If this is on Linux, I am surprised
>>> that you didn't get killed by the lseek() contention problem on a
>>> machine with that many cores.

>> Hm ... now that you mention it, all of these tests have been using
>> the latest-and-greatest unreleased RHEL kernels.

> It should be pretty easy to figure it out, though.   Just fire up
> pgbench with lots of clients (say, 160) and run vmstat in another
> window.  If the machine reports 10% system time, it's fixed.  If it
> reports 90% system time, it's not.

I ran it up to "pgbench -c 200 -j 200 -S -T 300 bench" and still see
vmstat numbers around 50% user time, 12% system time, 38% idle.
So no lseek problem here, boss.  Kernel calls itself 2.6.32-192.el6.x86_64.

			regards, tom lane

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