From: Ming Lei <ming.lei@canonical.com>
To: Prarit Bhargava <prarit@redhat.com>
Cc: 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: Wed, 23 Oct 2013 21:21:33 +0800 [thread overview]
Message-ID: <CACVXFVPSyNu6rUuDrqT2YZVucSgyeDN_toS-Y+WoT7Ye15iGRA@mail.gmail.com> (raw)
In-Reply-To: <5267BAE7.2090300@redhat.com>
On Wed, Oct 23, 2013 at 8:02 PM, Prarit Bhargava <prarit@redhat.com> 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.
>
> Which is terrible... so HOTPLUG doesn't work here.
>
> Let me back up Ming and see if you have a better solution for me. I have a
> system that does not have the x86 microcode loaded on disk. I use the microcode
> module which calls request_firmware_nowait() to load the microcode image and I
> want it done as fast as possible. The microcode loader does not have a uevent
> so I'm not waiting on userspace for completion.
>
> How do I avoid the 60 second delay/cpu introduced in the microcode path? I
> don't see one. If I use HOTPLUG I'm waiting 60 seconds. If I use NOHOTPLUG
> AFAICT the loading function never will return. AFAICT the same issue arises
> with the dell_rbu code -- it appears to never load the dell_rbu firmware.
As I said, the 60 second delay is from udev, so that is the root cause.
There are some workarounds for your reference:
- fix udev
- disable CONFIG_FW_LOADER_USER_HELPER if you are sure
the microcode image is under the default firmware search paths, which
are defined in drivers/base/firmware_class.c
- fake a empty latest microcode image under your firmware path
- use request_firmware_nowait(HOTPLUG) to request firmware from
user space, and apply the microcode at a appropriate time after the
request is completed, and the approach is what we are discussing.
Thanks,
--
Ming Lei
next prev parent reply other threads:[~2013-10-23 13:21 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 [this message]
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
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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