Re: heads up: Fix for intel hardware bug will lead to performance regressions - Mailing list pgsql-hackers

From Robert Haas
Subject Re: heads up: Fix for intel hardware bug will lead to performance regressions
Date
Msg-id CA+Tgmobs0YsYKPbhf_9DcrbO2xtso4A18jO+p=_hTw8x8abFLQ@mail.gmail.com
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In response to heads up: Fix for intel hardware bug will lead to performanceregressions  (Andres Freund <andres@anarazel.de>)
Responses Re: heads up: Fix for intel hardware bug will lead to performance regressions
List pgsql-hackers
On Tue, Jan 2, 2018 at 5:23 PM, Andres Freund <andres@anarazel.de> wrote:
> To get closer to the worst case, I've also measured:
>
> pgbench SELECT 1, 16 clients, i7-6820HQ CPU (skylake):
>
> pti=off:
> tps = 420490.162391
>
> pti=on:
> tps = 350746.065039 (~0.83x)
>
> pti=on, nopcid:
> tps = 324269.903152 (~0.77x)
>
>
> Note that real-world scenarios probably will see somewhat smaller
> impact, as this was measured over a loopback unix sockets which'll have
> smaller overhead itself than proper TCP sockets + actual network.

What about scenarios with longer-running queries?

Is it feasible to think about reducing the number of system calls we
issue in cases that weren't previously worth optimizing?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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