Re: 转发：[PATCH] NUMA spinlock [BZ #23962]

[H.J. Lu]

On Thu, Jan 3, 2019 at 6:52 AM Szabolcs Nagy <Szabolcs.Nagy@arm.com> wrote:
>
> On 03/01/2019 05:35, 马凌(彦军) wrote:
> >      create mode 100644 manual/examples/numa-spinlock.c
> >      create mode 100644 sysdeps/unix/sysv/linux/numa-spinlock-private.h
> >      create mode 100644 sysdeps/unix/sysv/linux/numa-spinlock.c
> >      create mode 100644 sysdeps/unix/sysv/linux/numa-spinlock.h
> >      create mode 100644 sysdeps/unix/sysv/linux/numa_spinlock_alloc.c
> >      create mode 100644 sysdeps/unix/sysv/linux/x86/tst-numa-variable-overhead.c
> >      create mode 100644 sysdeps/unix/sysv/linux/x86/tst-variable-overhead-skeleton.c
> >      create mode 100644 sysdeps/unix/sysv/linux/x86/tst-variable-overhead.c
>
> as far as i can tell the new code is generic
> (other than the presence of efficient getcpu),
> so i think the test should be generic too.
>
> >     --- /dev/null
> >     +++ b/sysdeps/unix/sysv/linux/x86/tst-variable-overhead-skeleton.c
> >     @@ -0,0 +1,384 @@
> ...
> >     +/* Check spinlock overhead with large number threads.  Critical region is
> >     +   very smmall.  Critical region + spinlock overhead aren't noticeable
> >     +   when number of threads is small.  When thread number increases,
> >     +   spinlock overhead become the bottleneck.  It shows up in wall time
> >     +   of thread execution.  */
>
> yeah, this is not easy to do in a generic way, i think
> even on x86 such measurement is problematic, you don't
> know what goes on a system (or vm) when the glibc test
> is running.
>
> but doing precise timing is not that important for
> checking the correctness of the locks, so i think a
> simplified version can be generic test code.

Here is the updated patch to make tests generic.

-- 
H.J.
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