From: David Howells <dhowells@redhat.com>
To: Andrea Arcangeli <andrea@suse.de>
Cc: David Howells <dhowells@redhat.com>,
Linus Torvalds <torvalds@transmeta.com>,
Manfred Spraul <manfred@colorfullife.com>,
Ulrich.Weigand@de.ibm.com, linux-kernel@vger.kernel.org
Subject: Re: Deadlock on the mm->mmap_sem
Date: Thu, 20 Sep 2001 00:25:40 +0100 [thread overview]
Message-ID: <7486.1000941940@warthog.cambridge.redhat.com> (raw)
In-Reply-To: Message from Andrea Arcangeli <andrea@suse.de> of "Wed, 19 Sep 2001 20:47:20 +0200." <20010919204720.L720@athlon.random>
Andrea Arcangeli <andrea@suse.de> wrote:
> On Wed, Sep 19, 2001 at 07:26:33PM +0100, David Howells wrote:
> > > if we go generic then I strongly recommend my version of the generic
> > > semaphores is _much_ faster (and cleaner) than this one
> >
> > Not so:-) Your patch, Andrea, grabs the spinlock far more than is necessary.
>
> then why your microbenchmarks says my version is much faster?
They don't:
[my rwsem-unfair-2.diff patch]
#rds #wrs time : rd granted [spread] wr granted [spread]
==== ==== ===== =================== ===================
1 0 10s: 25384639 [0.008%] 0 [0.000%]
2 0 10s: 8007388 [0.013%] 0 [0.000%]
4 0 10s: 8004833 [0.007%] 0 [0.000%]
0 1 10s: 0 [0.000%] 25717288 [0.009%]
0 4 10s: 0 [0.000%] 2817293 [2.323%]
4 2 10s: 12742523 [0.008%] 114 [5.394%]
30 1 10s: 12739163 [0.002%] 92 [1.739%]
30 15 50s: 63733591 [0.003%] 286 [2.711%]
[Andrea's 00_rwsem-19 patch]
#rds #wrs time : rd granted [spread] wr granted [spread]
==== ==== ===== =================== ===================
1 0 10s: 24577938 [0.003%] 0 [0.000%]
2 0 10s: 5631224 [0.016%] 0 [0.000%]
4 0 10s: 5633280 [0.009%] 0 [0.000%]
0 1 10s: 0 [0.000%] 24572785 [0.007%]
0 4 10s: 0 [0.000%] 3444786 [0.091%]
4 2 10s: 8036291 [0.008%] 122 [4.918%]
30 1 10s: 8036490 [0.006%] 89 [1.253%]
30 15 50s: 40200472 [0.001%] 265 [2.717%]
[Unpatched kernel]
#rds #wrs time : rd granted [spread] wr granted [spread]
==== ==== ===== =================== ===================
1 0 10s: 30118903 [0.008%] 0 [0.000%]
2 0 10s: 12543737 [0.007%] 0 [0.000%]
4 0 10s: 12543731 [0.006%] 0 [0.000%]
0 1 10s: 0 [0.000%] 28408147 [0.008%]
0 4 10s: 0 [0.000%] 1554495 [0.172%]
4 2 10s: 1119656 [0.076%] 560020 [0.077%]
30 1 10s: 5361923 [0.024%] 55787 [0.012%]
30 15 50s: 5322473 [0.049%] 2661621 [0.050%]
David
next prev parent reply other threads:[~2001-09-19 23:25 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-17 21:50 Deadlock on the mm->mmap_sem Manfred Spraul
2001-09-17 23:39 ` Linus Torvalds
[not found] ` <200109172339.f8HNd5W13244@penguin.transmeta.com>
2001-09-18 0:01 ` Andrea Arcangeli
2001-09-18 7:31 ` Manfred Spraul
2001-09-18 7:55 ` Andrea Arcangeli
2001-09-18 8:18 ` David Howells
2001-09-18 9:32 ` David Howells
2001-09-18 9:37 ` Manfred Spraul
2001-09-18 9:49 ` Arjan van de Ven
2001-09-18 12:53 ` Manfred Spraul
2001-09-18 14:13 ` David Howells
2001-09-18 14:49 ` Alan Cox
2001-09-18 15:26 ` David Howells
2001-09-18 15:46 ` Alan Cox
2001-09-18 15:11 ` David Howells
2001-09-18 16:49 ` Linus Torvalds
2001-09-19 9:51 ` David Howells
2001-09-19 12:49 ` Andrea Arcangeli
2001-09-19 14:08 ` Manfred Spraul
2001-09-19 14:51 ` David Howells
2001-09-19 15:18 ` Manfred Spraul
2001-09-19 14:53 ` David Howells
2001-09-19 18:03 ` Andrea Arcangeli
2001-09-19 18:16 ` Benjamin LaHaise
2001-09-19 18:27 ` David Howells
2001-09-19 18:48 ` Andrea Arcangeli
2001-09-19 18:45 ` Andrea Arcangeli
2001-09-19 21:14 ` Benjamin LaHaise
2001-09-19 22:07 ` Andrea Arcangeli
2001-09-19 18:19 ` Manfred Spraul
2001-09-20 2:07 ` Andrea Arcangeli
2001-09-20 4:37 ` Andrea Arcangeli
2001-09-20 7:05 ` David Howells
2001-09-20 7:19 ` Andrea Arcangeli
2001-09-20 8:01 ` David Howells
2001-09-20 8:09 ` Andrea Arcangeli
2001-09-19 18:26 ` David Howells
2001-09-19 18:47 ` Andrea Arcangeli
2001-09-19 23:25 ` David Howells [this message]
2001-09-19 23:34 ` Andrea Arcangeli
2001-09-19 23:46 ` Andrea Arcangeli
2001-09-19 23:24 ` [PATCH] attempt #2 (Re: Deadlock on the mm->mmap_sem) David Howells
2001-09-19 14:58 ` Deadlock on the mm->mmap_sem David Howells
[not found] <masp0008@stud.uni-sb.de>
2001-09-20 10:57 ` Studierende der Universitaet des Saarlandes
2001-09-20 12:40 ` David Howells
2001-09-20 18:24 ` Andrea Arcangeli
2001-09-20 21:43 ` Manfred Spraul
2001-09-22 21:06 ` Manfred Spraul
-- strict thread matches above, loose matches on Subject: below --
2001-09-18 13:22 Ulrich Weigand
2001-09-17 20:57 Ulrich Weigand
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7486.1000941940@warthog.cambridge.redhat.com \
--to=dhowells@redhat.com \
--cc=Ulrich.Weigand@de.ibm.com \
--cc=andrea@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=manfred@colorfullife.com \
--cc=torvalds@transmeta.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox