Re: [Qemu-devel] [PATCH] iov: avoid memcpy for "simple" iov_from_buf/iov_to_buf

[Stefan Hajnoczi]

On Fri, Dec 18, 2015 at 01:08:43PM +0800, Stefan Hajnoczi wrote:
> On Wed, Dec 16, 2015 at 11:57:33AM +0100, Paolo Bonzini wrote:
> > memcpy can take a large amount of time for small reads and writes.
> > For virtio it is a common case that the first iovec can satisfy the
> > whole read or write.  In that case, and if bytes is a constant to
> > avoid excessive growth of code, inline the first iteration
> > into the caller.
> > 
> > Signed-off-by: Paolo Bonzini <address@hidden>
> > ---
> >  include/qemu/iov.h | 32 ++++++++++++++++++++++++++++----
> >  util/iov.c         |  8 ++++----
> >  2 files changed, 32 insertions(+), 8 deletions(-)
> 
> Thanks, applied to my block-next tree:
> https://github.com/stefanha/qemu/commits/block-next

Paolo, I've dropped this from block-next because it breaks
tests/test-iov.

Please resolve the failure and submit a new patch.

Thanks,
Stefan

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