lkml.org 
[lkml]   [2008]   [Nov]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Unix sockets via TCP on localhost: is TCP slower?
Olaf van der Spek wrote:
> On Thu, Nov 13, 2008 at 12:24 PM, Arnaldo Carvalho de Melo
> <acme@redhat.com> wrote:
>> Em Thu, Nov 13, 2008 at 12:20:44AM +0100, Olaf van der Spek escreveu:
>>> Hi,
>>>
>>> Quite often in discussions, I see people claiming Unix sockets are
>>> faster then TCP sockets on a connection that stays inside localhost.
>>> Let's say from app A to app B.
>>> Is this indeed the case and if so, how much and why?
>>> My assumption is that the kernel can optimize the 'connection' and let
>>> any performance differences disappear.
>> How much? Please measure.

Lmbench shows local tcp as noticeably slower than unix sockets on a Mac
G5 running 2.6.27.


*Local* Communication latencies in microseconds - smaller is better
---------------------------------------------------------------
Host OS 2p/0K Pipe AF UDP RPC/ TCP RPC/ TCP
ctxsw UNIX UDP TCP conn
--------- ------- ----- ----- ---- ----- ----- ----- ----- ----
localhost 2.6.27 2.270 10.5 12.6 19.9 31.5 22.7 35.5 68.




*Local* Communication bandwidths in MB/s - bigger is better
-----------------------------------------------------------------------
Host OS Pipe AF TCP File Mmap Bcopy Bcopy Mem Mem
UNIX reread reread (libc) (hand) read write
--------- ------- ---- ---- ---- ------ ------ ------ ------ ---- -----
localhost 2.6.27 1368 1564 334. 1111.8 2068.8 930.3 947.0 2072 1269.




Chris


\
 
 \ /
  Last update: 2008-11-14 00:07    [W:0.067 / U:0.128 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site