linux-kernel - Re: [PATCH 2/7] locking/rwsem: more aggressive use of optimistic spinning

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Message-ID: <1408174826.5575.33.camel@marge.simpson.net>
Date:	Sat, 16 Aug 2014 09:40:26 +0200
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Waiman Long <waiman.long@...com>
Cc:	Dave Chinner <david@...morbit.com>, Jason Low <jason.low2@...com>,
	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org, Davidlohr Bueso <davidlohr@...com>,
	Scott J Norton <scott.norton@...com>
Subject: Re: [PATCH 2/7] locking/rwsem: more aggressive use of optimistic
 spinning

On Fri, 2014-08-15 at 13:58 -0400, Waiman Long wrote:

> Thank for the testing recipe. I am afraid that I can't find a 500TB SSD 
> for testing purpose. Do you think the test will still be valid for 
> exercising rwsem if I use a smaller SSD or maybe mechanical hard disk?

I suspect fs_mark will fit in less than a cubic meter of silicon.  You
definitely don't want to use a 400GB USB2 drive to find out though. 

FSUse%        Count         Size    Files/sec     App Overhead
     0       800000            0      22474.9          5551907
     0      1600000            0       1550.0        314304154
     0      2400000            0        832.3        928216719

zzzzz... nope, nobody is _that_ bored ^C 

(starts xfs_repair, perf top.. snort)

Nope, you definitely don't want USB2 crapware for that either :)

	-Mike

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