Messages in this thread | | | Subject | Re: [PATCH v2 1/3] lib/string: optimized memcpy | From | Ben Dooks <> | Date | Fri, 2 Jul 2021 15:37:19 +0100 |
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On 02/07/2021 13:31, Matteo Croce wrote: > From: Matteo Croce <mcroce@microsoft.com> > > Rewrite the generic memcpy() to copy a word at time, without generating > unaligned accesses. > > The procedure is made of three steps: > First copy data one byte at time until the destination buffer is aligned > to a long boundary. > Then copy the data one long at time shifting the current and the next long > to compose a long at every cycle. > Finally, copy the remainder one byte at time. > > This is the improvement on RISC-V: > > original aligned: 75 Mb/s > original unaligned: 75 Mb/s > new aligned: 114 Mb/s > new unaligned: 107 Mb/s > > and this the binary size increase according to bloat-o-meter: > > Function old new delta > memcpy 36 324 +288 > > > Signed-off-by: Matteo Croce <mcroce@microsoft.com> > --- > lib/string.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 77 insertions(+), 3 deletions(-)
Doesn't arch/riscv/lib/memcpy.S also exist for an architecture optimised version? I would have thought the lib/string.c version was not being used?
-- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius
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