Date: Mon, 09 May 2005 18:31:19 +0100 From: Pete French <petefrench@ticketswitch.com> To: ewan@mathcode.net, scottl@samsco.org Cc: freebsd-stable@freebsd.org Subject: Re: Performance issue Message-ID: <E1DVC6B-000FgV-9j@dilbert.firstcallgroup.co.uk> In-Reply-To: <427F9890.7010104@samsco.org>
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> 5.3 ships with SMP turned on, which makes lock operations rather
> expensive on single-processor machines. 4.x does not have SMP
> turned on by default. Would you be able to re-run your test with
> SMP turned off?
I just ran a test here with SMP turned of on 5.4-RC4 (GENERIC) I got the
following result:
67.52 real 41.13 user 26.16 sys
7034 involuntary context switches
i.e. it still has system time a a huge proportion of the total compared
to the 4.11 kernel. Interesingly, after reading Holger Kipp's results
I tried it on a genuine multi-processor box with SMP enabled running 5.3.
He got a very small percentage of the time in sys (3.51 out of 81.90) but
I got:
255.30 real 160.20 user 88.50 sys
Once again a far higher proprtion of the time spent in sys than you would
expect.
-pcf.
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