| From: | Greg Stark <gsstark(at)mit(dot)edu> |
|---|---|
| To: | John A Meinel <john(at)arbash-meinel(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Magnus Hagander <mha(at)sollentuna(dot)net>, Ken Egervari <ken(at)upfactor(dot)com>, pgsql-performance(at)postgresql(dot)org, pgsql-hackers-win32(at)postgresql(dot)org |
| Subject: | Re: [PERFORM] Help with tuning this query (with |
| Date: | 2005-03-07 18:05:30 |
| Message-ID: | 874qfnbac5.fsf@stark.xeocode.com |
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| Lists: | pgsql-hackers-win32 pgsql-performance |
John A Meinel <john(at)arbash-meinel(dot)com> writes:
> Then we would only be wrong for 256 gettimeofday calls. I agree it isn't
> great, though. And probably better to just abstract (possibly just with
> #ifdef) the calls for accurate timing, from the calls that actually need
> the real time.
What would be really neato would be to use the rtdsc (sp?) or equivalent
assembly instruction where available. Most processors provide such a thing and
it would give much lower overhead and much more accurate answers.
The main problem I see with this would be on multi-processor machines.
(QueryPerformanceCounter does work properly on multi-processor machines,
right?)
--
greg
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