From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Waiman Long <waiman.long@hpe.com>, Jason Low <jason.low2@hpe.com>,
Ding Tianhong <dingtianhong@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <Will.Deacon@arm.com>, Ingo Molnar <mingo@redhat.com>,
Imre Deak <imre.deak@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
Terry Rudd <terry.rudd@hpe.com>,
"Paul E. McKenney" <paulmck@us.ibm.com>,
Jason Low <jason.low2@hp.com>
Subject: Re: [RFC][PATCH 0/3] locking/mutex: Rewrite basic mutex
Date: Tue, 23 Aug 2016 22:34:17 +0200 [thread overview]
Message-ID: <20160823203417.GV10153@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CA+55aFyw9hmbsKx8m6V9hzuJ6ZNpaoJD9g=q0Du1kTdoT5FH7w@mail.gmail.com>
On Tue, Aug 23, 2016 at 02:53:07PM -0400, Linus Torvalds wrote:
> On Tue, Aug 23, 2016 at 12:17 PM, Davidlohr Bueso <dave@stgolabs.net> wrote:
> >
> >> 46 files changed, 160 insertions(+), 1298 deletions(-)
> >
> > Oh my.
>
> Yeah, that looks like a pretty compelling argument right there, if
> there isn't any other really major downside to this...
>
> Peter, is there some downside that isn't obvious? Like "Well, this
> does regress performance because it now always does X"?
The biggest difference is the mutex fast paths, where they were a single
atomic and branch they're now a bit bigger. How much that matters in
practise is something that we'll have to benchmark a bit.
Esp. the mutex_lock() fast-path now also needs to load current, which
at least should be fairly hot but can still be a number of dependent
loads on some archs.
prev parent reply other threads:[~2016-08-23 21:50 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-23 12:46 [RFC][PATCH 0/3] locking/mutex: Rewrite basic mutex Peter Zijlstra
2016-08-23 12:46 ` [RFC][PATCH 1/3] locking/mutex: Rework mutex::owner Peter Zijlstra
2016-08-23 19:55 ` Waiman Long
2016-08-23 20:52 ` Tim Chen
2016-08-23 21:03 ` Peter Zijlstra
2016-08-23 21:09 ` Peter Zijlstra
2016-08-23 20:17 ` Waiman Long
2016-08-23 20:31 ` Peter Zijlstra
2016-08-24 9:56 ` Will Deacon
2016-08-24 15:34 ` Peter Zijlstra
2016-08-24 16:52 ` Peter Zijlstra
2016-08-24 16:54 ` Will Deacon
2016-08-23 12:46 ` [RFC][PATCH 2/3] locking/mutex: Allow MUTEX_SPIN_ON_OWNER when DEBUG_MUTEXES Peter Zijlstra
2016-08-23 12:46 ` [RFC][PATCH 3/3] locking/mutex: Add lock handoff to avoid starvation Peter Zijlstra
2016-08-23 12:56 ` Peter Zijlstra
[not found] ` <57BCA869.1050501@hpe.com>
2016-08-23 20:32 ` Peter Zijlstra
2016-08-24 19:50 ` Waiman Long
2016-08-25 8:11 ` Peter Zijlstra
2016-08-23 16:17 ` [RFC][PATCH 0/3] locking/mutex: Rewrite basic mutex Davidlohr Bueso
2016-08-23 16:35 ` Jason Low
2016-08-23 16:57 ` Peter Zijlstra
2016-08-23 19:36 ` Waiman Long
2016-08-23 20:41 ` Peter Zijlstra
2016-08-23 22:34 ` Waiman Long
2016-08-24 1:13 ` Jason Low
2016-08-25 12:32 ` Peter Zijlstra
2016-08-25 15:43 ` Peter Zijlstra
2016-08-25 16:33 ` Waiman Long
2016-08-25 16:35 ` Peter Zijlstra
2016-08-27 18:27 ` Ingo Molnar
2016-08-25 19:11 ` huang ying
2016-08-25 19:26 ` Peter Zijlstra
2016-08-23 18:53 ` Linus Torvalds
2016-08-23 20:34 ` Peter Zijlstra [this message]
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=20160823203417.GV10153@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=Will.Deacon@arm.com \
--cc=dave@stgolabs.net \
--cc=dingtianhong@huawei.com \
--cc=imre.deak@intel.com \
--cc=jason.low2@hp.com \
--cc=jason.low2@hpe.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=paulmck@us.ibm.com \
--cc=terry.rudd@hpe.com \
--cc=tglx@linutronix.de \
--cc=tim.c.chen@linux.intel.com \
--cc=torvalds@linux-foundation.org \
--cc=waiman.long@hpe.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