[Pvfs2-developers] epoll fun
slang at mcs.anl.gov
Thu Oct 4 17:57:10 EDT 2007
On Oct 4, 2007, at 4:42 PM, Sam Lang wrote:
> 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.
> 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
Damnit, I forgot to recompile the servers. These results are with
poll. The slowdown still exists for these runs though.
>> 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
>>> that epoll_wait exhibits during operations over the VFS, and just
>>> the patterns they show at a scale of 100s of seconds (it almost
>>> like a seirpinski triangle). Not that it sheds much light on the
>> 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
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