linux-kernel - Re: [PATCH, v2] anon_vmas: Convert the rwsem to an rwlock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1380578642.29259.1.camel@schen9-mobl3>
Date:	Mon, 30 Sep 2013 15:03:58 -0700
From:	Tim Chen <tim.c.chen@...ux.intel.com>
To:	Waiman Long <waiman.long@...com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Rik van Riel <riel@...hat.com>,
	Peter Hurley <peter@...leysoftware.com>,
	Davidlohr Bueso <davidlohr.bueso@...com>,
	Alex Shi <alex.shi@...el.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Matthew R Wilcox <matthew.r.wilcox@...el.com>,
	Dave Hansen <dave.hansen@...el.com>,
	Michel Lespinasse <walken@...gle.com>,
	Andi Kleen <andi@...stfloor.org>,
	"Chandramouleeswaran, Aswin" <aswin@...com>,
	"Norton, Scott J" <scott.norton@...com>
Subject: Re: [PATCH, v2] anon_vmas: Convert the rwsem to an rwlock_t

On Mon, 2013-09-30 at 12:47 -0700, Tim Chen wrote:
> On Mon, 2013-09-30 at 15:35 -0400, Waiman Long wrote:
> > On 09/30/2013 03:23 PM, Tim Chen wrote:
> > > On Mon, 2013-09-30 at 20:14 +0200, Peter Zijlstra wrote:
> > >> On Mon, Sep 30, 2013 at 10:10:27AM -0700, Tim Chen wrote:
> > >>> Here's the exim workload data:
> > >>>
> > >>> rwsem improvment:
> > >>> Waimain's patch:        +2.0%
> > >>> Alex+Tim's patchset:    +4.8%
> > >>> Waiman+Alex+Tim:        +5.3%
> > >>>
> > >>> convert rwsem to rwlock_t for root anon_vma lock
> > >>> Ingo's patch		+11.7%
> > >>>
> > >> What happens if you stuff Waiman's qrwlock patches on top of that?
> > >> admittedly and oft mentioned in this thread, our current rwlock_t is
> > >> somewhat suboptimal under a number of conditions.
> > > I've tested with Waiman's qrwlock patches on top of Ingo's patches.
> > > It does not affect the throughput for exim and I still get
> > > about +11.7% throughput change (same as with Ingo's patch only).
> > >
> > > Tim
> > >
> > 
> > My qrwlock doesn't enable qrwlock by default. You have to use menuconfig 
> > to explicitly enable it. Have you done that when you build the test 
> > kernel? I am thinking of explicitly enabling it for x86 if the anon-vma 
> > lock is converted back to a rwlock.
> > 
> 
> Yes, I have explicitly enabled it during my testing.
> 
The workload I have is dominated by writer locks, with only very
occasional readers. So it may not benefit from the various tweaks you
have put in qrwlock.

Tim 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/