Am 26.03.2013 um 11:46 schrieb Juan Quintela <quint...@redhat.com>: > Peter Lieven <p...@kamp.de> wrote: >> this is v5 of my patch series with various optimizations in >> zero buffer checking and migration tweaks. >> >> thanks especially to Eric Blake, Orit Wassermann and Paolo Bonzini >> for reviewing. >> >> v5: >> - move zero splat vector to a different patch >> - fix indentation of can_user_buffer_find_nonzero_offset() >> - do not unroll the first loop in buffer_find_nonzero_offset() >> to optimize it for zero page checking >> - use an older unrolled version of find_next_bit() without >> SIMD instruction as there is no evidence that the vectorized >> version is better if not even worse and the code is easier >> to understand. >> - added a word in the commit message of patch 8 >> about the skipped pages field in QMP MigrationStats. >> - fixed the order of key-value pairs of MigrationStats in >> qapi-schema.json >> - updated info about the performance benefit of is_zero_page() >> to the latest benchmark results in the commit message. >> >> v4: >> - do not inline buffer_find_nonzero_offset() >> - inline can_usebuffer_find_nonzero_offset() correctly >> - readd asserts in buffer_find_nonzero_offset() as profiling >> shows they do not hurt. >> - change last occurences of scalar 8 by >> BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR >> - avoid deferencing p already in patch 5 where we >> know that the page (p) is zero >> - explicitly set bytes_sent = 0 if we skip a zero page. >> bytes_sent was 0 before, but it was not obvious. >> - add accounting information for skipped zero pages >> - fix errors reported by checkpatch.pl >> >> v3: >> - remove asserts, inline functions and add a check >> function if buffer_find_nonzero_offset() can be used. >> - use above check function in buffer_is_zero() and >> find_next_bit(). >> - use buffer_is_nonzero_offset() directly to find >> zero pages. we know that all requirements are met >> for memory pages. >> - fix C89 violation in buffer_is_zero(). >> - avoid derefencing p in ram_save_block() if we already >> know the page is zero. >> - fix initialization of last_offset in reset_ram_globals(). >> - avoid skipping pages with offset == 0 in bulk stage in >> migration_bitmap_find_and_reset_dirty(). >> - compared to v1 check for zero pages also after bulk >> ram migration as there are guests (e.g. Windows) which >> zero out large amount of memory while running. >> >> v2: >> - fix description, add trivial zero check and add asserts >> to buffer_find_nonzero_offset. >> - add a constant for the unroll factor of buffer_find_nonzero_offset >> - replace is_dup_page() by buffer_is_zero() >> - added test results to xbzrle patch >> - optimize descriptions >> >> Peter Lieven (10): >> move vector definitions to qemu-common.h >> add a zero splat vector to qemu-common.h >> cutils: add a function to find non-zero content in a buffer >> buffer_is_zero: use vector optimizations if possible >> bitops: unroll while loop in find_next_bit() >> migration: search for zero instead of dup pages >> migration: add an indicator for bulk state of ram migration >> migration: do not sent zero pages in bulk stage >> migration: do not search dirty pages in bulk stage >> migration: use XBZRLE only after bulk stage > > Really nice series.
Thank you. > I did some minor review changes, but they are more nits that anynthing > else. Ok, where is your repository? Peter > > Thanks, Juan. > > Reviewed-by: Juan Quintela <quint...@redhat.com>
