Messages in this thread | | | From | PrasannaKumar Muralidharan <> | Date | Sun, 26 Nov 2017 18:21:36 +0530 | Subject | Re: [PATCH] lib: memmove: Use optimised memcpy if possible |
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Hi Dan,
On 26 November 2017 at 02:10, Dan Carpenter <dan.carpenter@oracle.com> wrote: > Paul's original patch should have been separated into two patches to > begin with. The patch does two different things and one part goes > through the MIPS tree and one part goes through Andrew, probably.
Okay. I will split his patch into two and send with my modifications.
> On Sat, Nov 25, 2017 at 10:52:04PM +0530, PrasannaKumar Muralidharan wrote: >> Hi, >> >> On 4 October 2017 at 22:26, PrasannaKumar Muralidharan >> <prasannatsmkumar@gmail.com> wrote: >> > When there is no overlap between src and dst use optimised memcpy if it >> > is available. >> > >> > Signed-off-by: Paul Burton <paul.burton@imgtec.com> >> > Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> >> > --- >> > This change is a small part of a patch [1] from Paul Burton. I have >> > added his Signed-off by. I do not know whether it is correct. Please let >> > me know if it has to be changed, I will send a v2. > > > Sign-off is like signing a legal document. Read > Documentation/process/submitting-patches.rst the section about > "11) Sign your work - the Developer's Certificate of Origin" for an > explanation. > > So, yeah, Paul provided his s-o-b and it needs to be here as well. But > also he maybe should get authorship credit. Just put the first line in > the email as: > > From: Paul Burton <paul.burton@imgtec.com> > > But that's sort of a trickier thing, so maybe put some explanation that > you chopped out a bit from Pauls patch in the changelog: > > This is part of a patch that Paul Burton wrote > https://patchwork.linux-mips.org/patch/14517/ > > I know you put that here, but since it's under the --- cut off it won't > be saved in the final git log.
Sure. Will do.
>> > >> > This patch is boot tested with qemu for MIPS architecture by removing >> > mips's memmove routine. This patch does not contain MIPS changes. I >> > will try to find out why [1] was not taken already and figure out what >> > to do. >> > > > Instead of boot testing, it would be better if we had a benchmark to > show it helped speed things up.
I will try to come up with some reasonable benchmark and post its results.
>> > 1. https://patchwork.linux-mips.org/patch/14517/ >> > >> > lib/string.c | 11 +++++++++++ >> > 1 file changed, 11 insertions(+) >> > >> > diff --git a/lib/string.c b/lib/string.c >> > index 9921dc2..462ab7b 100644 >> > --- a/lib/string.c >> > +++ b/lib/string.c >> > @@ -825,6 +825,17 @@ void *memmove(void *dest, const void *src, size_t count) >> > char *tmp; >> > const char *s; >> > >> > +#ifdef __HAVE_ARCH_MEMCPY >> > + /* Use optimised memcpy when there is no overlap */ >> > + const char *s_end = src + count; >> > + const char *d = dest; >> > + char *d_end = dest + count; >> > + >> > + s = src; >> > + if ((d_end <= s) || (s_end <= d)) >> > + return memcpy(dest, src, count); >> > +#endif /* __HAVE_ARCH_MEMCPY */ >> > + >> > if (dest <= src) { >> > tmp = dest; >> > s = src; >> > -- >> > 2.10.0 >> > >> >> Is there anything more that I have to do for this patch? >> > > Probably a patch like this needs to go through Andrew. Send it again > and CC Andrew Morton <akpm@linux-foundation.org>. It would be nice if > we could CC a better list than LKML but I don't know which one... Few > people read LKML.
I will add Andrew. Get maintainer script gave me a small list of email id for this. I don't know if there is a better way than using get_maintainer.pl.
> regards, > dan carpenter
Thanks a lot for your time Dan.
Thanks, PrasannaKumar
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