Re: [PATCH-tip v5 17/21] TP-futex: Group readers together in wait queue

[valdis . kletnieks]

On Fri, 03 Feb 2017 13:03:50 -0500, Waiman Long said:

> On a 2-socket 36-core E5-2699 v3 system (HT off) running on a 4.10

>                           WW futex       TP futex         Glibc
>                           --------       --------         -----
> Total locking ops        35,707,234     58,645,434     10,930,422
> Per-thread avg/sec           99,149        162,887         30,362
> Per-thread min/sec           93,190         38,641         29,872
> Per-thread max/sec          104,213        225,983         30,708

Do we understand where the 38K number came from?  I'm a bit concerned that the
min-to-max has such a large dispersion compared to all the other numbers.  Was
that a worst-case issue, and is the worst-case something likely to happen in
production, or requires special effort to trigger?

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