Re: [PATCH] riscv: use the generic string routines

From: Palmer Dabbelt
Date: Wed Aug 04 2021 - 16:40:22 EST

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:

original aligned: 75 Mb/s
original unaligned: 75 Mb/s
new aligned: 114 Mb/s
new unaligned: 107 Mb/s

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>


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?