| From: | Dilip Kumar <dilipbalaut(at)gmail(dot)com> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Speed up Clog Access by increasing CLOG buffers |
| Date: | 2016-10-21 02:44:05 |
| Message-ID: | CAFiTN-tvJTGCvR=5gRUorX66j5ALjnZwfu1vmAR9g7i1_Vf3aQ@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Thu, Oct 20, 2016 at 9:15 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> So here's my theory. The whole reason why Tomas is having difficulty
> seeing any big effect from these patches is because he's testing on
> x86. When Dilip tests on x86, he doesn't see a big effect either,
> regardless of workload. But when Dilip tests on POWER, which I think
> is where he's mostly been testing, he sees a huge effect, because for
> some reason POWER has major problems with this lock that don't exist
> on x86.
Right, because on POWER we can see big contention on ClogControlLock
with 300 scale factor, even at 96 client count, but on X86 with 300
scan factor there is almost no contention on ClogControlLock.
However at 1000 scale factor we can see significant contention on
ClogControlLock on X86 machine.
I want to test on POWER with 1000 scale factor to see whether
contention on ClogControlLock become much worse ?
I will run this test and post the results.
--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com
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