On Wed, Oct 23, 2013 at 8:02 PM, Prarit Bhargava <pra...@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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
