This patchset removes the current x86 dependency for zsmalloc and introduces some performance improvements in the object mapping paths. It was meant to be a follow-on to my previous patchest https://lkml.org/lkml/2012/6/26/540 However, this patchset differed so much in light of new performance information that I mostly started over. In the past, I attempted to compare different mapping methods via the use of zcache and frontswap. However, the nature of those two features makes comparing mapping method efficiency difficult since the mapping is a very small part of the overall code path. In an effort to get more useful statistics on the mapping speed, I wrote a microbenchmark module named zsmapbench, designed to measure mapping speed by calling straight into the zsmalloc paths. https://github.com/spartacus06/zsmapbench This exposed an interesting and unexpected result: in all cases that I tried, copying the objects that span pages instead of using the page table to map them, was _always_ faster. I could not find a case in which the page table mapping method was faster. zsmapbench measures the copy-based mapping at ~560 cycles for a map/unmap operation on spanned object for both KVM guest and bare-metal, while the page table mapping was ~1500 cycles on a VM and ~760 cycles bare-metal. The cycles for the copy method will vary with allocation size, however, it is still faster even for the largest allocation that zsmalloc supports. The result is convenient though, as mempcy is very portable :) This patchset replaces the x86-only page table mapping code with copy-based mapping code. It also makes changes to optimize this new method further. There are no changes in arch/x86 required. Patchset is based on greg's staging-next. Seth Jennings (4): zsmalloc: remove x86 dependency zsmalloc: add single-page object fastpath in unmap zsmalloc: add details to zs_map_object boiler plate zsmalloc: add mapping modes drivers/staging/zcache/zcache-main.c | 6 +- drivers/staging/zram/zram_drv.c | 7 +- drivers/staging/zsmalloc/Kconfig | 4 - drivers/staging/zsmalloc/zsmalloc-main.c | 124 ++++++++++++++++++++++-------- drivers/staging/zsmalloc/zsmalloc.h | 14 +++- drivers/staging/zsmalloc/zsmalloc_int.h | 6 +- 6 files changed, 114 insertions(+), 47 deletions(-) -- 1.7.9.5 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
