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

[Palmer Dabbelt]

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?