On 04/09/2013 02:53 PM, Paolo Bonzini wrote: > Il 09/04/2013 13:43, Juan Quintela ha scritto: >>>> @@ -687,12 +685,10 @@ void qemu_put_byte(QEMUFile *f, int v) >>>> f->bytes_xfer++; >>>> if (f->ops->writev_buffer) { >>>> add_to_iovec(f, f->buf + f->buf_index, 1); >>>> - f->buf_index++; >>>> - } else { >>>> - f->buf_index++; >>>> - if (f->buf_index == IO_BUF_SIZE) { >>>> - qemu_fflush(f); >>>> - } >>>> + } >>>> + f->buf_index++; >>>> + if (f->buf_index == IO_BUF_SIZE) { >>>> + qemu_fflush(f); >>>> } >>>> } >> If you follow my advice of moving the call to add_to_iovec() you get >> this one simplified and only one place to do this. > > Moving what call? The apparent complication is because the old logic > was a bit more involute than necessary. If you look at the code after > the patches, not the patches themselves, you'll see for yourself. > > The logic now is: > > add byte > if using iovs > add byte to iov list > if buffer full > flush > > add_to_iovec has no business checking the buffer. Why should > qemu_put_buffer_async() check the buffer? > > The duplication between qemu_put_byte and qemu_put_buffer is a different > topic. I think it's acceptable in the name of performance, but perhaps > you can just call qemu_put_buffer(f, &c, 1). I thought about it too, we can keep the optimization by checking the size
Orit > > Paolo >