maria-developers team mailing list archive

[Davi Arnaut <davi@xxxxxxxxxxxxxxx>]

Hi Sergey,

I looked into fast mutex in the past [1] and was never able to get a
straight answer (even from the original developer) on what was the
intention behind it and how it made things faster as it actually made
things slower in the past (Bug#38941, others). There is a comment in
http://bugs.mysql.com/bug.php?id=58766 highlighting one case where I saw a
small performance improvement, but even that was highly workload/hardware
dependent (can't recall which workload exactly, might have been sysbench's
point select or something similar).

1. http://dev.mysql.com/worklog/task/?id=4601



On Wed, Feb 26, 2014 at 10:36 PM, Sergey Vojtovich <svoj@xxxxxxxxxxx> wrote:

> Hi Sergei,
>
> do you know if we ship any binaries with fast mutex
> (-DMY_PTHREAD_FASTMUTEX)
> enabled or officially suggest it? What was it's intention and what loads
> it was
> supposed to make faster?
>
> I'm trying to understand if fastmutex is worth fixing. It looks like
> duplication
> of PTHREAD_MUTEX_ADAPTIVE_NP, so we have double spinning when they're
> enabled.
> According to my recent benchmarks it shown worst performance.
>
> Thanks,
> Sergey
>
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