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Re: Massive performance regression of glibc string functions

On Fri, Nov 06, 2009 at 10:20:41AM -0700, H.J. Lu wrote:
> I am using the rdtsc timing in glibc string tests. Here is strlen data on
> Intel(R) Xeon(R) CPU           X3350  @ 2.66GHz
> Data on memcmp and strcmp show similar results. The new ones
> in glibc 2.11 are much better than the old ones in glibc 2.9.

I think the one you have shown exactly matches my findings - I also
think strlen() in glibc-2.11 is much better than in glibc-2.9 (except on
AMD and very small strings). But that is the only one of these I tested;
could you please post the same numbers for e.g. memcmp()?

> If you believe there is a regression, please provide length as well
> as alignments on input data. I will take a look.

The lengths are the numbers after function names - i.e. I'm testing with
4, 8, 32 and 128. All the values are 8-aligned, I can test misaligned
strings too if you think 2.11 will do better there.

				Petr "Pasky" Baudis
A lot of people have my books on their bookshelves.
That's the problem, they need to read them. -- Don Knuth

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