From: Palmer Dabbelt > Sent: 04 August 2021 21:40 > > On Tue, 03 Aug 2021 09:54:34 PDT (-0700), mcroce@xxxxxxxxxxxxxxxxxxx wrote: > > On Mon, Jul 19, 2021 at 1:44 PM Matteo Croce <mcroce@xxxxxxxxxxxxxxxxxxx> wrote: > >> > >> From: Matteo Croce <mcroce@xxxxxxxxxxxxx> > >> > >> Use the generic routines which handle alignment properly. > >> > >> These are the performances measured on a BeagleV machine for a > >> 32 mbyte buffer: > >> > >> memcpy: > >> original aligned: 75 Mb/s > >> original unaligned: 75 Mb/s > >> new aligned: 114 Mb/s > >> new unaligned: 107 Mb/s > >> > >> memset: > >> original aligned: 140 Mb/s > >> original unaligned: 140 Mb/s > >> new aligned: 241 Mb/s > >> new unaligned: 241 Mb/s > >> > >> TCP throughput with iperf3 gives a similar improvement as well. > >> > >> This is the binary size increase according to bloat-o-meter: > >> > >> add/remove: 0/0 grow/shrink: 4/2 up/down: 432/-36 (396) > >> Function old new delta > >> memcpy 36 324 +288 > >> memset 32 148 +116 > >> strlcpy 116 132 +16 > >> strscpy_pad 84 96 +12 > >> strlcat 176 164 -12 > >> memmove 76 52 -24 > >> Total: Before=1225371, After=1225767, chg +0.03% > >> > >> Signed-off-by: Matteo Croce <mcroce@xxxxxxxxxxxxx> > >> Signed-off-by: Emil Renner Berthing <kernel@xxxxxxxx> > >> --- > > > > Hi, > > > > can someone have a look at this change and share opinions? > > This LGTM. How are the generic string routines landing? I'm happy to > take this into my for-next, but IIUC we need the optimized generic > versions first so we don't have a performance regression falling back to > the trivial ones for a bit. Is there a shared tag I can pull in? I thought the actual problem was that the asm copy functions were doing misaligned transfers and faulting. There is no way that the simple C loop should be as fast as the asm function given the delay cycles reading from memory. You definitely need to test much smaller copies where the buffers are resident in the L1 data cache. Anything else is completely dominated by the cache line fills/spills. You also need to test on the much faster riscv implementations not just on the beaglev board. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
