| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, Marko Tiikkaja <marko(at)joh(dot)to>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Noah Misch <noah(at)leadboat(dot)com> |
| Subject: | Re: kqueue |
| Date: | 2016-09-13 20:34:53 |
| Message-ID: | 28060.1473798893@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Andres Freund <andres(at)anarazel(dot)de> writes:
> On 2016-09-13 15:37:22 -0400, Tom Lane wrote:
>> (It's a 4-core CPU so I saw little point in pressing harder than
>> that.)
> I think in reality most busy machines, were performance and scalability
> matter, are overcommitted in the number of connections vs. cores. And
> if you look at throughput graphs that makes sense; they tend to increase
> considerably after reaching #hardware-threads, even if all connections
> are full throttle busy.
At -j 10 -c 10, all else the same, I get 84928 TPS on HEAD and 90357
with the patch, so about 6% better.
>> So at this point I'm wondering why Thomas and Heikki could not measure
>> any win. Based on my results it should be easy. Is it possible that
>> OS X is better tuned for multi-CPU hardware than FreeBSD?
> Hah!
Well, there must be some reason why this patch improves matters on OS X
and not FreeBSD ...
regards, tom lane
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