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

[Palmer Dabbelt]

On Thu, 05 Aug 2021 03:31:04 PDT (-0700), mcroce@xxxxxxxxxxxxxxxxxxx wrote:
> On Wed, Aug 4, 2021 at 10:40 PM Palmer Dabbelt <palmer@xxxxxxxxxxx> wrote:
> > 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?
>
> Hi,
>
> I see them only in linux-next by now.

These ended up getting rejected by Linus, so I'm going to hold off on 
this for now.  If they're really out of lib/ then I'll take the C 
routines in arch/riscv, but either way it's an issue for the next 
release.