Re: [PATCH] Fix kmem_cache_free performance regression in slab

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, 29 Nov 2007 12:05:13 -0700 Matthew Wilcox <[email protected]> wrote:

> The database performance group have found that half the cycles spent
> in kmem_cache_free are spent in this one call to BUG_ON.  Moving it
> into the CONFIG_SLAB_DEBUG-only function cache_free_debugcheck() is a
> performance win of almost 0.5% on their particular benchmark.
> 
> The call was added as part of commit ddc2e812d592457747c4367fb73edcaa8e1e49ff
> with the comment that "overhead should be minimal".  It may have been
> minimal at the time, but it isn't now.
> 

It is worth noting that the offending commit hit mainline in June 2006.

It takes a very long time for some performance regressions to be
discovered.  By which time it is effectively too late to fix it.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux