| Message ID | 20240315140823.2478146-1-willy@infradead.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: Increase folio batch size | expand |
> include/linux/pagevec.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h > index fcc06c300a72..5d3a0cccc6bf 100644 > --- a/include/linux/pagevec.h > +++ b/include/linux/pagevec.h > @@ -11,8 +11,8 @@ > > #include <linux/types.h> > > -/* 15 pointers + header align the folio_batch structure to a power of two */ > -#define PAGEVEC_SIZE 15 > +/* 31 pointers + header align the folio_batch structure to a power of two */ > +#define PAGEVEC_SIZE 31 > > struct folio; > Hi, Thanks for the patch. I tested the patch with will-it-scale page-fault2 on AMD Zen 4 EPYC server (2-socket system with 128 cores per socket, SMT Enabled). Increasing the folio batch size from 15 to 31 gives following performance improvement: Median: 8.32% Max: 23.15% 99th percentile: 20.95% There is slight performance degradation (bound by -1.21%) in a few cases. The patch seems to be beneficial for AMD systems as well. Tested-by: Shivank Garg <shivankg@amd.com> -- Best Regards, Shivank
On 15.03.24 15:08, Matthew Wilcox (Oracle) wrote: > On a 104 thread, 2 socket Skylake system, Intel report a 4.7% performance > reduction with will-it-scale page_fault2. This was due to reducing the > size of the batch from 32 to 15. Increasing the folio batch size from > 15 to 31 gives a performance increase of 12.5% relative to the original, > or 17.2% relative to the reduced performance commit. > > The penalty of this commit is an additional 128 bytes of stack usage. > Six folio_batches are also allocated from percpu memory in cpu_fbatches > so that will be an additional 768 bytes of percpu memory (per CPU). > Tim Chen originally submitted a patch like this in 2020: > https://lore.kernel.org/linux-mm/d1cc9f12a8ad6c2a52cb600d93b06b064f2bbc57.1593205965.git.tim.c.chen@linux.intel.com/ > > Tested-by: Yujie Liu <yujie.liu@intel.com> > Fixes: 99fbb6bfc16f ("mm: make folios_put() the basis of release_pages()") > Reported-by: kernel test robot <oliver.sang@intel.com> > Closes: https://lore.kernel.org/oe-lkp/202403151058.7048f6a8-oliver.sang@intel.com > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > include/linux/pagevec.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h > index fcc06c300a72..5d3a0cccc6bf 100644 > --- a/include/linux/pagevec.h > +++ b/include/linux/pagevec.h > @@ -11,8 +11,8 @@ > > #include <linux/types.h> > > -/* 15 pointers + header align the folio_batch structure to a power of two */ > -#define PAGEVEC_SIZE 15 > +/* 31 pointers + header align the folio_batch structure to a power of two */ > +#define PAGEVEC_SIZE 31 > > struct folio; > Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h index fcc06c300a72..5d3a0cccc6bf 100644 --- a/include/linux/pagevec.h +++ b/include/linux/pagevec.h @@ -11,8 +11,8 @@ #include <linux/types.h> -/* 15 pointers + header align the folio_batch structure to a power of two */ -#define PAGEVEC_SIZE 15 +/* 31 pointers + header align the folio_batch structure to a power of two */ +#define PAGEVEC_SIZE 31 struct folio;