Re: Major network performance regression in 3.7

Eric Dumazet
2013-01-06T19:00:15Z

On Sun, 2013-01-06 at 10:51 -0800, Eric Dumazet wrote:
> >
> > (sd->len is usually 4096, which is expected, but sd->total_len value is
> > huge in your case, so we always set the flag in fs/splice.c)
>
> I am testing :
>
> if (sd->len < sd->total_len && pipe->nrbufs > 1)
> more |= MSG_SENDPAGE_NOTLAST;
>

Yes, this should fix the problem :

If there is no following buffer in the pipe, we should not set NOTLAST.

diff --git a/fs/splice.c b/fs/splice.c
index 8890604..6909d89 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -696,8 +696,10 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe,
return -EINVAL;

more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0;
- if (sd->len < sd->total_len)
+
+ if (sd->len < sd->total_len && pipe->nrbufs > 1)
more |= MSG_SENDPAGE_NOTLAST;
+
return file->f_op->sendpage(file, buf->page, buf->offset,
sd->len, &pos, more);
}