Commit Graph

6 Commits

Author SHA1 Message Date
Peter Lieven 49f676a00a bitops: unroll while loop in find_next_bit()
this patch adopts the loop unrolling idea of bitmap_is_zero() to
speed up the skipping of large areas with zeros in find_next_bit().

this routine is extensively used to find dirty pages in
live migration.

testing only the find_next_bit performance on a zeroed bitfield
the loop onrolling decreased executing time by approx. 50% on x86_64.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2013-03-26 13:32:32 +01:00
Richard Henderson 0f9d8bd386 bitops: Replace bitops_ctol with ctzl
The is the only remaining user.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-02-16 11:12:45 +00:00
Richard Henderson 4932398fac bitops: Inline bitops_flsl
This is the only remaining user.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-02-16 11:12:37 +00:00
Richard Henderson 265ce4a5ca bitops: Use non-bitops ctzl
The use of ctz has already eliminated zero, and thus the difference
in edge conditions between the two routines is irrelevant.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-02-16 11:12:04 +00:00
Paolo Bonzini fbeadf50f2 bitops: unify bitops_ffsl with the one in host-utils.h, call it bitops_ctzl
We had two copies of a ffs function for longs with subtly different
semantics and, for the one in bitops.h, a confusing name: the result
was off-by-one compared to the library function ffsl.

Unify the functions into one, and solve the name problem by calling
the 0-based functions "bitops_ctzl" and "bitops_ctol" respectively.

This also fixes the build on platforms with ffsl, including Mac OS X
and Windows.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Andreas Färber <afaerber@suse.de>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-02-02 20:16:00 +00:00
Paolo Bonzini baacf04799 build: move libqemuutil.a components to util/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-12 18:42:50 +01:00