Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932618Ab3ICIoZ (ORCPT ); Tue, 3 Sep 2013 04:44:25 -0400 Received: from vaxjo.synopsys.com ([198.182.60.75]:38272 "EHLO vaxjo.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932473Ab3ICIoW convert rfc822-to-8bit (ORCPT ); Tue, 3 Sep 2013 04:44:22 -0400 From: Vineet Gupta To: Manfred Spraul CC: Linus Torvalds , Davidlohr Bueso , Sedat Dilek , Davidlohr Bueso , linux-next , LKML , Stephen Rothwell , Andrew Morton , linux-mm , Andi Kleen , Rik van Riel , "Jonathan Gonzalez" Subject: Re: ipc-msg broken again on 3.11-rc7? Thread-Topic: ipc-msg broken again on 3.11-rc7? Thread-Index: AQHOpZ5oa2zPW4yZMkWQwZduFtEUDA== Date: Tue, 3 Sep 2013 08:44:17 +0000 Message-ID: References: <1372192414.1888.8.camel@buesod1.americas.hpqcorp.net> <1372202983.1888.22.camel@buesod1.americas.hpqcorp.net> <521DE5D7.4040305@synopsys.com> <52205597.3090609@synopsys.com> <5224BCF6.2080401@colorfullife.com> Accept-Language: en-US, en-IN Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.12.239.235] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2629 Lines: 71 On 09/02/2013 09:59 PM, Manfred Spraul wrote: > Hi, > > [forgot to cc everyone, thus I'll summarize some mails...] > On 09/02/2013 06:58 AM, Vineet Gupta wrote: >> On 08/31/2013 11:20 PM, Linus Torvalds wrote: >>> Vineet, actual patch for what Davidlohr suggests attached. Can you try it? >>> >>> Linus >> Apologies for late in getting back to this - I was away from my computer for a bit. >> >> Unfortunately, with a quick test, this patch doesn't help. >> FWIW, this is latest mainline (.config attached). >> >> Let me know what diagnostics I can add to help with this. > msgctl08 is a bulk message send/receive test. I had to look at it once > before, then it was a broken hardware: > https://lkml.org/lkml/2008/6/12/365 > This can be ruled out, because it works with 3.10. > > msgctl08 uses pairs of threads: one thread does msgsnd(), the other one > msgrcv(). > There is no synchronization, i.e. the msgsnd() can race ahead until the > kernel buffer is full and then a block with msgrcv() follows or it could > be pairs of alternating msgsnd()/msgrcv() operations. > No special features are used: each pair of threads has it's own message > queues, all messages have type=1. > > Vineet ran strace - and just before the signal from killing msgctl08, > there are only msgsnd()/msgrcv() calls. > Vineet: > a) could you run strace tomorrow again, with '-ttt' as an additional > option? I don't see where exactly it hangs. Yet to do this. > b) Could you check that it is not just a performance regression? > Does ./msgctl08 1000 16 hang, too? Nope that doesn't hang. The minimal configuration that hangs reliably is msgctl 50000 2 With this config there are 3 processes. ... 555 554 root S 1208 0.4 0 0.0 ./msgctl08 50000 2 554 551 root S 1208 0.4 0 0.0 ./msgctl08 50000 2 551 496 root S 1208 0.4 0 0.0 ./msgctl08 50000 2 ... [ARCLinux]$ cat /proc/551/stack [<80aec3c6>] do_wait+0xa02/0xc94 [<80aecad2>] SyS_wait4+0x52/0xa4 [<80ae24fc>] ret_from_system_call+0x0/0x4 [ARCLinux]$ cat /proc/555/stack [<80c2950e>] SyS_msgrcv+0x252/0x420 [<80ae24fc>] ret_from_system_call+0x0/0x4 [ARCLinux]$ cat /proc/554/stack [<80c28c82>] do_msgsnd+0x116/0x35c [<80ae24fc>] ret_from_system_call+0x0/0x4 Is this a case of lost wakeup or some such. I'm running with some more diagnostics and will report soon ... -Vineet -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/