Re: Performance degradation in commit 6150a1b0

On March 31, 2016 7:16:33 AM GMT+02:00, Noah Misch <noah(at)leadboat(dot)com> wrote:
>On Thu, Mar 31, 2016 at 01:10:56AM -0400, Noah Misch wrote:
>> On Sun, Mar 27, 2016 at 02:15:50PM +0200, Andres Freund wrote:
>> > On 2016-03-27 02:34:32 +0530, Ashutosh Sharma wrote:
>> > > As mentioned in my earlier mail i was not able to apply
>> > > *pinunpin-cas-5.patch* on commit *6150a1b0,
>> >
>> > That's not surprising; that's pretty old.
>> >
>> > > *therefore i thought of applying it on the latest commit and i
>was
>> > > able to do it successfully. I have now taken the performance
>readings
>> > > at latest commit i.e. *76281aa9* with and without applying
>> > > *pinunpin-cas-5.patch* and my observations are as follows,
>> > >
>> >
>> > > 1. I can still see that the current performance lags by 2-3% from
>the
>> > > expected performance when *pinunpin-cas-5.patch *is applied on
>the commit
>> > >
>> > > *76281aa9.*
>> > > 2. When *pinunpin-cas-5.patch *is ignored and performance is
>measured at
>> > > commit *76281aa9 *the overall performance lags by 50-60% from the
>expected
>> > > performance.
>> > >
>> > > *Note:* Here, the expected performance is the performance
>observed before
>> > > commit *6150a1b0 *when* ac1d794 *is reverted.
>> >
>> > Thanks for doing these benchmarks. What's the performance if you
>revert
>> > 6150a1b0 on top of a recent master? There've been a lot of other
>patches
>> > influencing performance since 6150a1b0, so minor performance
>differences
>> > aren't necessarily meaningful; especially when that older version
>then
>> > had other patches reverted.
>>
>> [This is a generic notification.]
>>
>> The above-described topic is currently a PostgreSQL 9.6 open item.
>Andres,
>> since you committed the patch believed to have created it, you own
>this open
>> item. If that responsibility lies elsewhere, please let us know
>whose
>> responsibility it is to fix this. Since new open items may be
>discovered at
>> any time and I want to plan to have them all fixed well in advance of
>the ship
>> date, I will appreciate your efforts toward speedy resolution.
>Please
>> present, within 72 hours, a plan to fix the defect within seven days
>of this
>> message. Thanks.
>
>My attribution above was incorrect. Robert Haas is the committer and
>owner of
>this one. I apologize.

Fine in this case I guess. I've posted a proposal nearby either way, it appears to be a !x86 problem.

Andres
--
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