Re: [PATCH] slub: reduce overhead of slub_debug

[Pekka Enberg]

On Thu, 7 Jul 2011, Pekka Enberg wrote:
> > Looks good to me. Christoph, David, ?

On Thu, 2011-07-07 at 13:17 -0500, Christoph Lameter wrote:
> The reason debug code is there is because it is useless overhead typically
> not needed. There is no point in optimizing the code that is not run in
> production environments unless there are gross performance issues that
> make debugging difficult. A performance patch for debugging would have to
> cause significant performance improvements. This patch does not do that
> nor was there such an issue to be addressed in the first place.

Is there something technically wrong with the patch? Quoting the patch
email:

  (Compiling some project with different options)
                                 make -j12    make clean
  slub_debug disabled:             1m 27s       1.2 s
  slub_debug enabled:              1m 46s       7.6 s
  slub_debug enabled + this patch: 1m 33s       3.2 s

  check_bytes still shows up high, but not always at the top.

That's significant enough speedup for me!

			Pekka

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