On Mon, Jul 02, 2012 at 04:15:48PM -0500, Seth Jennings wrote: > 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. Which architecture was this under? It sounds x86-ish? Is this on Westmere and more modern machines? What about Core2 architecture? Oh how did it work on AMD Phenom boxes? > > 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 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>