[Pvfs2-developers] epoll fun

[Sam Lang]

On Oct 4, 2007, at 3:45 PM, Pete Wyckoff wrote:

> slang at mcs.anl.gov wrote on Thu, 04 Oct 2007 15:21 -0500:
>> I'm in the process of getting a trace and dump from the same server
>> during the same runs.
>
> Good, will be interesting too see tcpdump + strace.

Pete,

Here's a trace and dump from the same set of runs.

http://www.mcs.anl.gov/~slang/epoll-trace.out [370MB]
http://www.mcs.anl.gov/~slang/server-packets.dump [180MB]

Again, the trace isn't from strace, I'm tracing the epoll calls  
manually.
-sam


>   Although I
> worry we might not learn anything new.
>
>> In the meantime, I attached two "zoomed" plots of the last one I
>> sent, with ranges set to 5000-5200 secs and 5000-6000 secs,
>> respectively.  I thought they were interesting, both for the behavior
>> that epoll_wait exhibits during operations over the VFS, and just for
>> the patterns they show at a scale of 100s of seconds (it almost looks
>> like a seirpinski triangle).  Not that it sheds much light on the
>> problem.
>
> Pretty.  Maybe there's a category for Most Attractive Unexplained
> Distributed System Art in the state fair this year.
>
> Would the pending request ID stuff with slog etc be useful in
> tracking individual operations?
>
> 		-- Pete
>