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 for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:	Mon, 16 May 2016 06:38:52 -0700
From:	Eric Dumazet <edumazet@...gle.com>
To:	Paolo Abeni <pabeni@...hat.com>
Cc:	Eric Dumazet <eric.dumazet@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>,
	netdev <netdev@...r.kernel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Jiri Pirko <jiri@...lanox.com>,
	Daniel Borkmann <daniel@...earbox.net>,
	Alexei Starovoitov <ast@...mgrid.com>,
	Alexander Duyck <aduyck@...antis.com>,
	Tom Herbert <tom@...bertland.com>,
	Ingo Molnar <mingo@...nel.org>, Rik van Riel <riel@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: Re: [RFC PATCH 0/2] net: threadable napi poll loop

On Mon, May 16, 2016 at 6:10 AM, Paolo Abeni <pabeni@...hat.com> wrote:
>
> I'm sorry for the not-so-prompt reply. I had to use a different H/W, so
> I had to re-run the tests with all the patch flavors to get comparable
> results.
>
> While I can confirm that adding the '!ksoftirqd_running()' condition
> improves the throughput a little, but in a reproducible way, removing
> the '!in_interrupt()' don't change the result measurably, in my
> environment.
>
> While running the test against a kernel with the above chunk applied I
> got a couple of:
>
> [  702.791025] NOHZ: local_softirq_pending 08
>
> Not seen with the other versions of this patch.

I've seen this message in all versions, depending on the workload.

Either a barrier of some kind is missing, or we uncover an existing bug.

Note that in my tests on an older base kernel (something based on 3.11
but with thousands of patches),
I would not have the scary rcu messages that I got with current
upstream kernels.

Powered by blists - more mailing lists