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[AF_UNIX]: use shift instead of integer division

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The patch below replaces a divide by 2 with a shift -- sk_sndbuf is an
integer, so gcc emits an idiv, which takes 10x longer than a shift by 1.
This improves af_unix bandwidth by ~6-10K/s.  Also, tidy up the comment
to fit in 80 columns while we're at it.

Signed-off-by: Benjamin LaHaise <benjamin.c.lahaise@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Benjamin LaHaise 2006-03-20 21:29:05 -08:00 committed by David S. Miller
parent 231d06ae82
commit e9df7d7f58
1 changed files with 5 additions and 5 deletions
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10
net/unix/af_unix.c
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@ -1427,15 +1427,15 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
while(sent < len)
{
/*
* Optimisation for the fact that under 0.01% of X messages typically
* need breaking up.
* Optimisation for the fact that under 0.01% of X
* messages typically need breaking up.
*/
size=len-sent;
size = len-sent;
/* Keep two messages in the pipe so it schedules better */
if (size > sk->sk_sndbuf / 2 - 64)
size = sk->sk_sndbuf / 2 - 64;
if (size > ((sk->sk_sndbuf >> 1) - 64))
size = (sk->sk_sndbuf >> 1) - 64;
if (size > SKB_MAX_ALLOC)
size = SKB_MAX_ALLOC;