On 10/28/2013 11:05 AM, Takashi Iwai wrote: > At Mon, 28 Oct 2013 08:06:08 -0400, > Prarit Bhargava wrote: >> >> If no firmware is found on the system that matches the processor, the >> microcode module can take hours to load. For example on recent kernels >> when loading the microcode module on an Intel system: >> >> [ 239.532116] microcode: CPU0 sig=0x306e4, pf=0x1, revision=0x413 >> [ 299.693447] microcode: CPU1 sig=0x306e4, pf=0x1, revision=0x413 >> [ 359.821972] microcode: CPU2 sig=0x306e4, pf=0x1, revision=0x413 >> [ 419.960263] microcode: CPU3 sig=0x306e4, pf=0x1, revision=0x413 >> [ 480.090024] microcode: CPU4 sig=0x306e4, pf=0x1, revision=0x413 >> ... >> [ 2825.151364] microcode: CPU43 sig=0x306e4, pf=0x1, revision=0x413 >> [ 2885.280863] microcode: CPU44 sig=0x306e4, pf=0x1, revision=0x413 >> [ 2945.410719] microcode: CPU45 sig=0x306e4, pf=0x1, revision=0x413 >> [ 3005.540541] microcode: CPU46 sig=0x306e4, pf=0x1, revision=0x413 >> [ 3065.670405] microcode: CPU47 sig=0x306e4, pf=0x1, revision=0x413 >> ... >> etc. >> >> Similarly there is a 60 second "hang" when loading the AMD module, which >> isn't as bad as the Intel situation. This is because the AMD microcode >> loader only attempts to look for the firmware on the boot_cpu and, if >> found, loads the microcode on each cpu. This patch does the same for the >> Intel microcode, and it obviously peeds up the module load if there is no >> microcode update available. >> >> After making this change, the old microcode loading code and the new >> loading code can be cleaned up and unified in the core code. >> >> This patch was tested on several systems (both AMD and Intel) with the >> microcode in place and without, as well as on several different OSes. > > Does simply disabling CONFIG_FW_LOADER_USER_HELPER work without your > patch? > > If yes, it's an infamous udev issue. An easier solution would be to > create a function that does only the direct f/w loading without > usermode helper, and call it in the microcode driver. > > An untested quick fix patch is attached below. > >
Takashi, this patch works AFAICT. I wish I had thought of doing it this way to begin with ... If you choose to submit, can you add a Tested-by: Prarit Bhargava <[email protected]> Thanks, P. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
