On Tue, Jul 09, 2013 at 10:14:34AM +0200, Peter Zijlstra wrote: > On Mon, Jul 08, 2013 at 10:24:34PM -0400, Vince Weaver wrote: > > > > So something like they have on ARM? > > > > vince@pandaboard:/sys/bus/event_source/devices$ ls -l > > lrwxrwxrwx 1 root root 0 Jul 8 21:57 ARMv7 Cortex-A9 -> > > ../../../devices/ARMv7 Cortex-A9 > > lrwxrwxrwx 1 root root 0 Jul 8 21:57 breakpoint -> > > ../../../devices/breakpoint > > lrwxrwxrwx 1 root root 0 Jul 8 21:57 software -> ../../../devices/software > > lrwxrwxrwx 1 root root 0 Jul 8 21:57 tracepoint -> > > ../../../devices/tracepoint > > Right so what I remember of the ARM case is that their /proc/cpuinfo isn't > sufficient to identify their PMU. And they don't have a cpuid like instruction > at all. > > > > For the cpu you can obviously just detect what processor you're on with > > > cpuid or whatever, but it's a bit of a hack. And that really doesn't > > > work for non-cpu PMUs. > > > > why is it a hack to use cpuid? > > I agree, for x86 cpuid is perfectly fine, as would /proc/cpuinfo be, I suspect > that just the model number is sufficient in most cases, even for uncore stuff. What about things on PCI? Other strange buses?
As long as everything's in /sys then it should be _possible_ for userspace to work out what's what, but it's going to end up with a bunch of detection logic and heuristics in the library. At which point you've just rewritten libpfm4. cheers _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
