From: Nix <nix@esperi.org.uk>
To: Dave Chinner <david@fromorbit.com>
Cc: Avery Pennarun <apenwarr@gmail.com>,
Rob Browning <rlb@defaultvalue.org>,
Robert Evans <evansr@google.com>,
bup-list <bup-list@googlegroups.com>,
linux-xfs@vger.kernel.org
Subject: Re: bupsplit.c copyright and patching
Date: Wed, 02 May 2018 09:57:03 +0100 [thread overview]
Message-ID: <871seuxwo0.fsf@esperi.org.uk> (raw)
In-Reply-To: <20180424164740.2eftsje7su5usmqs@destitution> (Dave Chinner's message of "Wed, 25 Apr 2018 02:47:40 +1000")
On 24 Apr 2018, Dave Chinner said:
> Yes, the problem still exists. CFQ just doesn't work well with
> workloads that issue concurrent, dependent IOs from multiple
> processes, nor does it work well with hardware raid arrays with
> non-volatile caches that have unpredictable IO performance. This
> sort of workload and hardware is common in the sorts of high
> performance applications we see run on XFS filesystems, and we avoid
> CFQ as much as possible....
Oh! I thought its problem was with concurrent *independent* I/Os. If
it's fine with those, and you're using md (not hardware RAID) it sounds
like the wost problems with CFQ may be avoided? (This is probably not
too surprising in hindsight, since those are the characteristics of
things like kernel compile runs, the one workload Linux will always work
well with!)
prev parent reply other threads:[~2018-05-02 8:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <6179db6e-786d-40a2-936d-9fb4dfa2529f@googlegroups.com>
[not found] ` <87k1uak2xb.fsf@trouble.defaultvalue.org>
[not found] ` <CAHqTa-1eKSZq6Vph+th5YH-b43NAvF+BWCDoJqPJQGa3=Oze-w@mail.gmail.com>
[not found] ` <874llde5yn.fsf@trouble.defaultvalue.org>
[not found] ` <CAHqTa-1ghU6+Y0Y2pBOjbS=7CWKMytPvj-c1Z0aE3=PqpPi1OA@mail.gmail.com>
[not found] ` <87k1u0ca2d.fsf@trouble.defaultvalue.org>
[not found] ` <CAHqTa-0B-iZfjhX4pHMnb0d-XRhY_wCywsjOOnOgSRF1iFKN4Q@mail.gmail.com>
[not found] ` <871sfsefs7.fsf@esperi.org.uk>
[not found] ` <CAHqTa-25QqzDb+u9_4zXuoMGU5uF9nv_pmioLE+xJ+0pHbiYUg@mail.gmail.com>
[not found] ` <87k1szdni5.fsf@esperi.org.uk>
[not found] ` <CAHqTa-28D05VafHNeS0f16qHQ9A6g=Vb8u=YEODquniwfEAygA@mail.gmail.com>
[not found] ` <871sf5ddi7.fsf@esperi.org.uk>
[not found] ` <CAHqTa-3KHrC67r9tZs5kFNF7bSh5Dt_AYHnAEhHziqvAijD_wA@mail.gmail.com>
2018-04-23 20:03 ` bupsplit.c copyright and patching Nix
2018-04-23 20:22 ` Avery Pennarun
2018-04-23 21:53 ` Nix
2018-04-23 22:06 ` Avery Pennarun
2018-04-24 16:47 ` Dave Chinner
2018-05-02 8:57 ` Nix [this message]
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