linux-kernel - Re: [RFC PATCH RT V3] rwsem: The return of multi-reader PI rwsems

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]

Date:	Fri, 11 Apr 2014 09:25:24 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Carsten Emde <C.Emde@...dl.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	linux-rt-users <linux-rt-users@...r.kernel.org>,
	Mike Galbraith <umgwanakikbuti@...il.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Clark Williams <williams@...hat.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>
Subject: Re: [RFC PATCH RT V3] rwsem: The return of multi-reader PI rwsems

On Fri, 11 Apr 2014 14:47:49 +0200
Carsten Emde <C.Emde@...dl.org> wrote:

> Hi Steven,
> 
> > [..] I added Carsten to the Cc, so I'll post the entire change log
> > of v1 here again.
> I've been listening and testing boxes all the time ...
> 

I figured but still wanted to add you to the Cc.

> > [..] If you have any benchmark on large machines I would be very
> > happy if you could test this patch against the unpatched version of
> > -rt.
> Three machines
> - an X32 x86_64 (AMD Opteron 6272 @2100 MHz) at rack #1/slot #1,
> - an X4x2 x86_64 (Intel i7-2600K @3400 MHz) at rack #4/slot #6, and
> - an X4 ARM (i.MX6 Quad @996 MHz) at rack #8/slot #7
> are running a v3-patched 3.12.15-rt25 kernel now. I'll equip more
> machines later.
> 
> What I can say so far is:
> - No evidence for any regression, no crashes

That's good to hear.

> - Performance certainly at least as good as unpatched, probably better

That's even better.

> 
> I'll do more tests and come back with more precise performance
> comparison data.

Do you also have any threaded tests? That is, something like a java
benchmark that kicks off lots of threads. That's where the performance
should show up the most. Clark's whack_mmap_sem test is specific to
this, and has shown an 10x increase in performance with my patch. But
that's a micro benchmark. A better test would be a real java
application.

Thanks,

-- Steve
--
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/