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From: Prarit Bhargava <prarit@redhat.com>
To: prarit@redhat.com
Cc: andrea.parri@amarulasolutions.com, brendanhiggins@google.com,
	gregkh@linuxfoundation.org, john.ogness@linutronix.de,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	peterz@infradead.org, pmladek@suse.com, rostedt@goodmis.org,
	sergey.senozhatsky@gmail.com, sergey.senozhatsky.work@gmail.com,
	tglx@linutronix.de, torvalds@linux-foundation.org
Subject: Re: [RFC PATCH v5 0/3] printk: new ringbuffer implementation
Date: Fri,  6 Dec 2019 09:16:53 -0500
Message-ID: <20191206141653.1199-1-prarit@redhat.com> (raw)
In-Reply-To: <87zhg6zx31.fsf@linutronix.de>

  John Ogness <john.ogness@linutronix.de> wrote:
> Hi Prarit,
> 
> On 2019-12-05, Prarit Bhargava <prarit@redhat.com> wrote:
> > Based on the comments there is going to be a v6 but in any case I am
> > starting testing of this patchset on several large core systems across
> > multiple architectures (x86_64, ARM64, s390, ppc64le).  Some of those
> > systems are known to fail boot due to the large amount of printk output so
> > it will be good to see if these changes resolve those issues.
> 
> Right now the patches only include the ringbuffer as a separate entity
> with a test module. So they do not yet have any effect on printk.
> 
> If you apply the patches and then build the "modules" target, you will
> have a new test_prb.ko module. Loading that module will start some heavy
> testing of the ringbuffer. As long as the testing is successful, the
> module will keep testing. During this time the machine will be very
> slow, but should still respond.
> 
> The test can be stopped by unloading the module. If the test stops on
> its own, then a problem was found. The output of the test is put into
> the ftrace buffer.
> 
> It would be nice if you could run the test module on some fat machines,
> at least for a few minutes to see if anything explodes. ARM64 and
> ppc64le will probably be the most interesting, due to memory barrier
> testing.
> 

I've run the module overnight on all 4 arches I mentioned above.  I didn't
see any failures but IIUC the module test runs at max.  I'm going to put a
load test on these systems that introduces a variable load to interfere
with the prbtest module to see if that kicks anything.

> Otherwise I will definitely be reaching out to you when we are ready to
> perform actual printk testing with the newly agreed up semantics
> (lockless, per-console printing threads, synchronous panic
> consoles). Thanks for your help with this.
>

np :) but I should be the one thanking you ;)

P.

> John Ogness


  reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-28  1:52 John Ogness
2019-11-28  1:52 ` [RFC PATCH v5 1/3] printk-rb: new printk ringbuffer implementation (writer) John Ogness
2019-12-02 15:48   ` Petr Mladek
2019-12-02 15:59     ` Petr Mladek
2019-12-02 16:37       ` John Ogness
2019-12-03  1:17         ` Sergey Senozhatsky
2019-12-03 14:18           ` Steven Rostedt
2019-12-05 12:01             ` John Ogness
2019-12-03  8:54         ` Petr Mladek
2019-12-03 14:13     ` John Ogness
2019-12-03 14:36       ` Petr Mladek
2019-12-09  9:19     ` Sergey Senozhatsky
2019-12-09  7:42   ` Sergey Senozhatsky
2019-12-09  9:00     ` John Ogness
2019-12-09  9:27   ` Sergey Senozhatsky
2019-12-09  9:34     ` John Ogness
2019-12-21 14:22   ` Andrea Parri
2019-12-23 16:01     ` John Ogness
2020-01-03 10:24       ` Petr Mladek
2020-01-04 14:33         ` Andrea Parri
2019-11-28  1:52 ` [RFC PATCH v5 2/3] printk-rb: new printk ringbuffer implementation (reader) John Ogness
2019-12-03 12:06   ` Petr Mladek
2019-12-03 13:46     ` John Ogness
2019-12-04 12:54       ` Petr Mladek
2019-12-04 13:28         ` John Ogness
2019-12-09  8:43   ` Sergey Senozhatsky
2019-12-09  9:03     ` Sergey Senozhatsky
2019-12-09  9:09     ` John Ogness
2019-11-28  1:52 ` [RFC PATCH v5 3/3] printk-rb: add test module John Ogness
2019-12-09  8:44   ` Sergey Senozhatsky
2019-12-05 13:46 ` [RFC PATCH v5 0/3] printk: new ringbuffer implementation Prarit Bhargava
2019-12-05 14:05   ` John Ogness
2019-12-06 14:16     ` Prarit Bhargava [this message]
2020-01-27 12:20 ` Eugeniu Rosca

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