Re: Possible performance regression in version 10.1 with pgbench read-write tests.

On Thu, Feb 22, 2018 at 7:55 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Wed, Feb 21, 2018 at 10:03 PM, Mithun Cy <mithun(dot)cy(at)enterprisedb(dot)com> wrote:
>> seeing futex in the call stack andres suggested that following commit could
>> be the reason for regression
>>
>> commit ecb0d20a9d2e09b7112d3b192047f711f9ff7e59
>> Author: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
>> Date: 2016-10-09 18:03:45 -0400
>>
>> Use unnamed POSIX semaphores, if available, on Linux and FreeBSD.
>>
>> Commenting out same in src/template/linux I did run the benchmark tests
>> again
>> performance improved from 26871.567326 to 34286.620251 (both median of 3
>> TPS).
>
> Hmm. So that commit might not have been the greatest idea.
>

It appears so. I think we should do something about it as the
regression is quite noticeable.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com