From: Prarit Bhargava <prarit@redhat.com>
To: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Ming Lei <ming.lei@canonical.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
x86@kernel.org,
Andreas Herrmann <herrmann.der.user@googlemail.com>,
tigran@aivazian.fsnet.co.uk
Subject: Re: [PATCH 1/2] firmware, fix request_firmware_nowait() freeze with no uevent
Date: Thu, 24 Oct 2013 08:05:50 -0400 [thread overview]
Message-ID: <52690D1E.6060400@redhat.com> (raw)
In-Reply-To: <20131024111737.GC24862@khazad-dum.debian.net>
On 10/24/2013 07:17 AM, Henrique de Moraes Holschuh wrote:
> On Wed, 23 Oct 2013, Prarit Bhargava wrote:
>> After all this I completely forgot the problem I'm trying to solve here. The
>> issue is that with HOTPLUG & request_microcode_nowait(), if the microcode image
>> is not found (that is the file is not found on disk), then EACH cpu waits 1
>> minute and it takes 2 hours for a 120 cpu box to load the microcode module.
>
> The proper fix seems to be teaching the concept of negative caching to the
> microcode core/drivers, as it was pointed out elsewhere in the thread.
> Negative caching should have a lifetime of "the current update-all-cores
> request".
>
Yes, I'm implementing v2 to do this already; caching the microcode is obvious.
I was actually looking at the code to see if there was a reason that each
processor needs to do a load request but cannot see one. I'm modifying the
microcode driver to do this, as I said, in v2.
> This would fix the absurd compound timeout delays, as on most systems it
> will result in just one timeout (the first one).
>
> That first timeout can be fixed by the user if they disable the userspace
> firmware loader helper. IMHO that might well be the best choice, as it is
> already the way forward.
The problem with that is I may have a configuration which depends on having the
userspace firmware loader helper for a device, but not the processors so IMO it
isn't a complete solution.
I've also toyed with the idea that there should be a request_firmware_timeout()
in which a timeout for HOTPLUG can be specified.
P.
next prev parent reply other threads:[~2013-10-24 12:06 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-20 21:35 [PATCH 0/2] Improve firmware loading times on AMD and Intel Prarit Bhargava
2013-10-20 21:35 ` [PATCH 1/2] firmware, fix request_firmware_nowait() freeze with no uevent Prarit Bhargava
2013-10-21 12:24 ` Ming Lei
2013-10-21 22:24 ` Prarit Bhargava
2013-10-22 2:35 ` Ming Lei
2013-10-22 23:15 ` Prarit Bhargava
2013-10-23 4:16 ` Ming Lei
2013-10-23 10:36 ` Prarit Bhargava
2013-10-23 12:02 ` Prarit Bhargava
2013-10-23 13:21 ` Ming Lei
2013-10-23 14:08 ` Prarit Bhargava
2013-10-24 1:54 ` Ming Lei
2013-10-24 11:17 ` Henrique de Moraes Holschuh
2013-10-24 12:05 ` Prarit Bhargava [this message]
2013-10-20 21:35 ` [PATCH 2/2] intel_microcode, Fix long microcode load time when firmware file is missing Prarit Bhargava
2013-10-21 12:20 ` Ming Lei
2013-10-21 12:26 ` Prarit Bhargava
2013-10-21 12:32 ` Ming Lei
2013-10-21 14:25 ` Prarit Bhargava
2013-10-22 2:43 ` Ming Lei
2013-10-22 23:16 ` Prarit Bhargava
2013-10-20 22:58 ` [PATCH 0/2] Improve firmware loading times on AMD and Intel Andi Kleen
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