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Date:      Thu, 21 Jan 2016 18:02:18 -0800
From:      Adrian Chadd <adrian.chadd@gmail.com>
To:        Benno Rice <benno@jeamland.net>
Cc:        Ryan Stone <rysto32@gmail.com>,  "<freebsd-transport@freebsd.org>" <freebsd-transport@freebsd.org>
Subject:   Re: Flamegraph of 8KB message bottlenecks
Message-ID:  <CAJ-Vmo=vbqRmBrh%2Bk3o6M-D-u=Q1%2Bb_j2beO2kG5PNgQzMe%2BAQ@mail.gmail.com>
In-Reply-To: <D856A593-F6CC-420D-9489-7C02A2567B76@jeamland.net>
References:  <CAFMmRNzBfNB7Fr3VYKJwHpxt1CBc4gT6Yh%2Bqx2u2O_K1KF3nxQ@mail.gmail.com> <CAJ-Vmo=CLt7xL04pTRui-qdsSeugsHqu3pCOYOKQT-mARPfEkg@mail.gmail.com> <CAFMmRNwwRmdEbBaL=pNzThHSA0skmhrsVH9sFkn-A2Txu=Q%2BnQ@mail.gmail.com> <CAJ-Vmokgtkx_Xjn6o9fbC3GyybBMNsX9Y9geLnznPMfxuHMTDA@mail.gmail.com> <D856A593-F6CC-420D-9489-7C02A2567B76@jeamland.net>

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On 21 January 2016 at 16:00, Benno Rice <benno@jeamland.net> wrote:
> The idb stuff is an Isilon-internal thing. It=E2=80=99s a different stora=
ge 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?


-a

>
>> On Jan 21, 2016, at 14:16, Adrian Chadd <adrian.chadd@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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