Messages in this thread | | | Subject | Re: [PATCH] perf/x86: check ucode before disabling PEBS on SandyBridge | From | Peter Zijlstra <> | Date | Fri, 15 Jun 2012 14:42:41 +0200 |
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On Fri, 2012-06-15 at 14:37 +0200, Borislav Petkov wrote: > This is a minimal fix which we'd like to see in stable too thus the > more-or-less arbitrary decision to allow system-wide reloading only on > the BSP: > > $ echo 1 > /sys/devices/system/cpu/cpu0/microcode/reload > ... > > and disable the interface on the other cores: > > $ echo 1 > /sys/devices/system/cpu/cpu23/microcode/reload > -bash: echo: write error: Invalid argument
One could allow the reload from all cpus and simply do all cpus, but I guess the rationale for not doing that and restricting it to cpu0 is to avoid the O(n^2) thing in case userspace issues a reload on all cpus?
If so it would be good to mention in the Changelog so people see its not a 'random' choice.
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