Re: heads up: Fix for intel hardware bug will lead to performance regressions

On Tue, Jan 2, 2018 at 5:23 PM, Andres Freund <andres(at)anarazel(dot)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
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