Flamegraph of 8KB message bottlenecks

Adrian Chadd adrian.chadd at gmail.com
Fri Jan 22 02:02:19 UTC 2016

On 21 January 2016 at 16:00, Benno Rice <benno at jeamland.net> wrote:
> The idb stuff is an Isilon-internal thing. It’s a different storage system for the file descriptor tables.

Ok. So hm, looking at that, i'd look at the syscall count breakdown to
see if you're doing very inefficient kqueue (eg add, trigger/remove,
read/write, add, etc.) rather than keeping it in the kqueue list.

But yeah, that fgets in the kqueue path and sleep lock contention in
the send path is hurting. :(

Maybe get a syscall breakdown, and maybe a lock profile trace?


>> On Jan 21, 2016, at 14:16, Adrian Chadd <adrian.chadd at gmail.com> wrote:
>> A lot of that syscall time is in kevent, doing fget locking. What kind
>> of filedescriptor is being used here? Just a normal socket, or is it
>> kqueue on some /dev entry or something?
>> What's that "idb_" stuff?
>> -a
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