lkml.org 
[lkml]   [2001]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Is sendfile all that sexy?


On Sun, 14 Jan 2001, Ingo Molnar wrote:

>
> i believe what you are seeing here is the overhead of the pagecache. When
> using sendmsg() only, you do not read() the file every time, right? Is

In that case just a user space buffer is sent i.e no file association.

> ttcp using multiple threads?

Only a single thread, single flow setup. Very primitive but simple.

> In that case if the sendfile() is using the
> *same* file all the time, creating SMP locking overhead.
>
> if this is the case, what result do you get if you use a separate,
> isolated file per process? (And i bet that with DaveM's pagecache
> scalability patch the situation would also get much better - the global
> pagecache_lock hurts.)
>

Already doing the single file, single process. However, i do run by time
which means i could read the file from the begining(offset 0) to the end
then re-do it for as many times as 15secs would allow. Does this affect
it? I tried one 1.5 GB file, it was oopsing and given my setup right now i
cant trace it. So i am using about 170M which is read about 8 times in
the 15 secs

cheers,
jamal

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:28    [W:0.154 / U:1.908 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site