Messages in this thread | | | Date | Sun, 14 Jan 2001 14:02:40 -0500 (EST) | From | jamal <> | Subject | Re: Is sendfile all that sexy? |
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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
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