On Sun, May 16, 2021 at 10:20:55PM +0200, Uladzislau Rezki (Sony) wrote: > Recently there has been introduced a page bulk allocator for > users which need to get number of pages per one call request. > > For order-0 pages switch to an alloc_pages_bulk_array_node() > instead of alloc_pages_node(), the reason is the former is > not capable of allocating set of pages, thus a one call is > per one page. > > Second, according to my tests the bulk allocator uses less > cycles even for scenarios when only one page is requested. > Running the "perf" on same test case shows below difference: > > <default> > - 45.18% __vmalloc_node > - __vmalloc_node_range > - 35.60% __alloc_pages > - get_page_from_freelist > 3.36% __list_del_entry_valid > 3.00% check_preemption_disabled > 1.42% prep_new_page > <default> > > <patch> > - 31.00% __vmalloc_node > - __vmalloc_node_range > - 14.48% __alloc_pages_bulk > 3.22% __list_del_entry_valid > - 0.83% __alloc_pages > get_page_from_freelist > <patch> > > The "test_vmalloc.sh" also shows performance improvements: > > fix_size_alloc_test_4MB loops: 1000000 avg: 89105095 usec > fix_size_alloc_test loops: 1000000 avg: 513672 usec > full_fit_alloc_test loops: 1000000 avg: 748900 usec > long_busy_list_alloc_test loops: 1000000 avg: 8043038 usec > random_size_alloc_test loops: 1000000 avg: 4028582 usec > fix_align_alloc_test loops: 1000000 avg: 1457671 usec > > fix_size_alloc_test_4MB loops: 1000000 avg: 62083711 usec > fix_size_alloc_test loops: 1000000 avg: 449207 usec > full_fit_alloc_test loops: 1000000 avg: 735985 usec > long_busy_list_alloc_test loops: 1000000 avg: 5176052 usec > random_size_alloc_test loops: 1000000 avg: 2589252 usec > fix_align_alloc_test loops: 1000000 avg: 1365009 usec > > For example 4MB allocations illustrates ~30% gain, all the > rest is also better. > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> FWIW, it passed build and boot tests. Acked-by: Mel Gorman <mgorman@xxxxxxx> -- Mel Gorman SUSE Labs
