Re: missing madvise functionality

Ulrich Drepper wrote:
In case somebody wants to play around with Rik patch or another
madvise-based patch, I have x86-64 glibc binaries which can use it:

http://people.redhat.com/drepper/rpms

These are based on the latest Fedora rawhide version. They should work
on older systems, too, but you screw up your updates. Use them only if
you know what you do.

By default madvise(MADV_DONTNEED) is used. With the environment variable

Cool. According to my thinking, madvise(MADV_DONTNEED) even in today's
kernels using down_write(mmap_sem) for MADV_DONTNEED is better than
mmap/mprotect, which have more fundamental locking requirements, more
overhead and no benefits (except debugging, I suppose).

MADV_DONTNEED is twice as fast in single threaded performance, and an
order of magnitude faster for multiple threads, when MADV_DONTNEED only
takes mmap_sem for read.

Do you plan to include this change in general glibc releases? Maybe it
will make google malloc obsolete? ;) (I don't suppose you'd be able to
get any tests done, Andrew?)

--
SUSE Labs, Novell Inc.
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