Messages in this thread | | | Subject | Re: [PATCH] slub: reduce overhead of slub_debug | From | Matt Mackall <> | Date | Thu, 07 Jul 2011 13:55:59 -0500 |
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On Thu, 2011-07-07 at 21:52 +0300, Pekka Enberg wrote: > 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!
We're not going to make any progress on this; Christoph conveniently forgets the counterarguments from week to week.
-- Mathematics is the supreme nostalgia of our time.
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