Re: benchmark results comparing versions 15.2 and 16

Поиск
Список
Период
Сортировка
От MARK CALLAGHAN
Тема Re: benchmark results comparing versions 15.2 and 16
Дата
Msg-id CAFbpF8PX6ETTtumBmdhU21hBRa=XnQ=7HqmqZTGE4McyDAvLeA@mail.gmail.com
обсуждение исходный текст
Ответ на Re: benchmark results comparing versions 15.2 and 16  (Andres Freund <andres@anarazel.de>)
Ответы Re: benchmark results comparing versions 15.2 and 16  (MARK CALLAGHAN <mdcallag@gmail.com>)
Список pgsql-hackers
Дерево обсуждения
I have two more runs of the benchmark in progress so we will have 3 results for each of the test cases to confirm that the small regressions are repeatable.

On Fri, May 5, 2023 at 1:34 PM Andres Freund <andres@anarazel.de> wrote:
 
One thing that's somewhat odd is that there's very marked changes in l.i0's
p99 latency for the four clients cases - but whether 15 or 16 are better
differs between the runs.

From the response time sections for l.i0 the [1ms, 4ms) bucket has 99% or more for all 6 cases. 
For example, https://mdcallag.github.io/reports/23_05_04_ibench.beelink.pg16b.1u.1tno.cached/all.html#l.i0.rt
But yes, the p99 is as you state. I will wade through my test scripts tomorrow to see how the p99 is computed.

I do wonder if there's something getting scheduled in some of these runs
increasing latency?

Do you mean interference from other processes? Both the big and small servers run Ubuntu 22.04 server (no X) and there shouldn't be many extra things, although Google Cloud adds a few extra things that run in the background. 
 
Or what we're seeing depends on the time between the start of the server and
the start of the benchmark? It is interesting that the per-second throughput
graph shows a lot of up/down at the end:
https://mdcallag.github.io/reports/23_05_04_ibench.beelink.pg16b.4u.1tyes.1g/tput.l.i0.html

Both 15 and 16 have one very high result at 70s, 15 then has one low, but 16
has two low results.

Immediately prior to l.i0 the database directory is wiped and then Postgres is initialized and started.

The IPS vs time graphs are more interesting for benchmark steps that run longer. Alas, this can't run too long if the resulting database is to fit in <= 16G. But that is a problem for another day. The IPS vs time graphs are not a flat line, but I am not ready to pursue that as problem unless it shows multi-second write-stalls (fortunately it does not).

--
Mark Callaghan
mdcallag@gmail.com

В списке pgsql-hackers по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: [PATCH] Add native windows on arm64 support
Следующее
От: "Drouvot, Bertrand"
Дата:
Сообщение: Re: Add two missing tests in 035_standby_logical_decoding.pl