| From: | Ants Aasma <ants(at)cybertec(dot)at> |
|---|---|
| To: | Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)uk> |
| Cc: | Merlin Moncure <mmoncure(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Florian Pflug <fgp(at)phlo(dot)org>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org, Stephen Frost <sfrost(at)snowman(dot)net> |
| Subject: | Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile |
| Date: | 2012-06-06 18:54:15 |
| Message-ID: | CA+CSw_uS1Sg=u-Q-B0QUGChwJs5_z4u7yx4YkvfbXbQj1oJP5A@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Wed, Jun 6, 2012 at 2:27 PM, Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)uk> wrote:
> I've quickly tested your lockfree-getbuffer.patch patch with the test case
> you provided and I barely see any improvement (2% at max)
> https://docs.google.com/open?id=0B7koR68V2nM1QVBxWGpZdW4wd0U
> tested with 24 core (48 ht cores, Xeon E7- 4807).
> Although the tps vs number of threads looks weird....
Was this the range scan on the test table? (sorry about the error in
the query, the x should really be id) In that case the results look
really suspicious. My machine (4 cores, no ht, @ 4GHz, newer arch)
peaked at 90tps with the stated configuration. Even when upping the
shared_buffers and enabling indexonlyscan I didn't see more than about
540tps per thread. The test is designed to exercise buffer eviction,
doing about 9800 buffer reads per transaction with 32MB of buffers.
Ants Aasma
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