Hello Petr, With your patch we get 5-10 percent performance improvement on s390.
Two examples: $ time ./makedumpfile -d 31 /proc/vmcore /dev/null -f user sys = total ===================================== With patches 0.156 0.248 0.404 Without patches 0.168 0.274 0.442 <- No idea why we save system time? $ time ./makedumpfile -d 0 /proc/vmcore /dev/null -f user sys = total ===================================== With patches 0.683 0.020 0.703 Without patches 0.714 0.019 0.733 Regards Michael On Fri, 6 Mar 2015 15:03:12 +0100 Petr Tesarik <ptesa...@suse.cz> wrote: > Because all pages must go into the cache, data is unnecessarily > copied from mmapped regions to cache. Avoid this copying by storing > the mmapped regions directly in the cache. > > First, the cache code needs a clean up clarification of the concept, > especially the meaning of the pending list (allocated cache entries > whose content is not yet valid). > > Second, the cache must be able to handle differently sized objects > so that it can store individual pages as well as mmapped regions. > > Last, the cache eviction code must be extended to allow either > reusing the read buffer or unmapping the region. > > Changelog: > v2: cache cleanup _and_ actuall mmap implementation > v1: only the cache cleanup > > Petr Tesarik (8): > cache: get rid of search loop in cache_add() > cache: allow to return a page to the pool > cache: do not allocate from the pending list > cache: add hit/miss statistics to the final report > cache: allocate buffers in one big chunk > cache: allow arbitrary size of cache entries > cache: store mapped regions directly in the cache > cleanup: remove unused page_is_fractional > > cache.c | 81 +++++++++++++++++---------------- > cache.h | 16 +++++-- > elf_info.c | 16 ------- > elf_info.h | 2 - > makedumpfile.c | 138 > ++++++++++++++++++++++++++++++++++----------------------- > 5 files changed, 138 insertions(+), 115 deletions(-) > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec