From mboxrd@z Thu Jan 1 00:00:00 1970 From: davem@davemloft.net (David Miller) Date: Tue, 29 Aug 2017 18:12:08 -0700 (PDT) Subject: [PATCH v7 07/11] sparc64: optimized struct page zeroing In-Reply-To: <1503972142-289376-8-git-send-email-pasha.tatashin@oracle.com> References: <1503972142-289376-1-git-send-email-pasha.tatashin@oracle.com> <1503972142-289376-8-git-send-email-pasha.tatashin@oracle.com> Message-ID: <20170829.181208.171985548699678313.davem@davemloft.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Pavel Tatashin Date: Mon, 28 Aug 2017 22:02:18 -0400 > Add an optimized mm_zero_struct_page(), so struct page's are zeroed without > calling memset(). We do eight to ten regular stores based on the size of > struct page. Compiler optimizes out the conditions of switch() statement. > > SPARC-M6 with 15T of memory, single thread performance: > > BASE FIX OPTIMIZED_FIX > bootmem_init 28.440467985s 2.305674818s 2.305161615s > free_area_init_nodes 202.845901673s 225.343084508s 172.556506560s > -------------------------------------------- > Total 231.286369658s 227.648759326s 174.861668175s > > BASE: current linux > FIX: This patch series without "optimized struct page zeroing" > OPTIMIZED_FIX: This patch series including the current patch. > > bootmem_init() is where memory for struct pages is zeroed during > allocation. Note, about two seconds in this function is a fixed time: it > does not increase as memory is increased. > > Signed-off-by: Pavel Tatashin > Reviewed-by: Steven Sistare > Reviewed-by: Daniel Jordan > Reviewed-by: Bob Picco You should probably use initializing stores when you are doing 8 stores and we thus know the page struct is cache line aligned. But other than that: Acked-by: David S. Miller