From: Waiman Long <waiman.long@hpe.com>
To: <Valdis.Kletnieks@vt.edu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Dave Hansen <dave.hansen@intel.com>,
"Chen, Tim C" <tim.c.chen@intel.com>,
Ingo Molnar <mingo@redhat.com>, Davidlohr Bueso <dbueso@suse.de>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Jason Low <jason.low2@hp.com>,
Michel Lespinasse <walken@google.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Waiman Long <waiman.long@hp.com>,
Al Viro <viro@zeniv.linux.org.uk>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: performance delta after VFS i_mutex=>i_rwsem conversion
Date: Tue, 7 Jun 2016 11:22:39 -0400 [thread overview]
Message-ID: <5756E6BF.9020908@hpe.com> (raw)
In-Reply-To: <77052.1465269772@turing-police.cc.vt.edu>
On 06/06/2016 11:22 PM, Valdis.Kletnieks@vt.edu wrote:
> On Mon, 06 Jun 2016 14:20:32 -0700, Linus Torvalds said:
>
>> I guess some "concurrent readdir with unlink" load would show that
>> behavior, but is it _realistic_? No idea. Let's not worry about it too
>> much until somebody shows a reason to worry.
> I've seen Makefiles where 'make clean' does a 'find . -name "*.o" | xargs rm'.
>
> But if somebody is doing that often enough against cache-cold directory trees
> to matter, they have bigger problems (like learning how to properly develop
> code using 'make'). So unless performance is *so* bad it triggers the lockup
> detector, it's probably OK....
>
The performance won't be very bad. It is just that with the right mix of
readers and writers, the performance can be a bit worse with i_rwsem
than with i_mutex. But in other cases, the performance will be
comparable or better with i_rwsem.
Regards,
Longman
next prev parent reply other threads:[~2016-06-07 15:23 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 20:00 performance delta after VFS i_mutex=>i_rwsem conversion Dave Hansen
2016-06-06 20:46 ` Linus Torvalds
2016-06-06 21:13 ` Waiman Long
2016-06-06 21:20 ` Linus Torvalds
2016-06-07 3:22 ` Valdis.Kletnieks
2016-06-07 15:22 ` Waiman Long [this message]
2016-06-08 8:58 ` Ingo Molnar
2016-06-09 10:25 ` Ingo Molnar
2016-06-09 18:14 ` Dave Hansen
2016-06-09 20:10 ` Chen, Tim C
2016-06-06 21:15 ` Al Viro
2016-06-06 21:46 ` Linus Torvalds
2016-06-06 22:07 ` Al Viro
2016-06-06 23:50 ` Linus Torvalds
2016-06-06 23:59 ` Linus Torvalds
2016-06-07 0:29 ` Linus Torvalds
2016-06-07 0:40 ` Al Viro
2016-06-07 0:44 ` Al Viro
2016-06-07 0:58 ` Al Viro
2016-06-07 0:58 ` Linus Torvalds
2016-06-07 1:19 ` Al Viro
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