Messages in this thread | | | Date | Thu, 2 Oct 2014 10:41:25 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 00/11] perf: Intel Cache QoS Monitoring support |
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On Thu, Oct 02, 2014 at 07:51:24AM +0100, Matt Fleming wrote: > On Wed, 01 Oct, at 02:42:05PM, Andi Kleen wrote: > > Matt Fleming <matt@console-pimps.org> writes: > > > > > > Changes in v2: > > > > > > - Added Jiri Olsa's Acked-by to PATCH 02/11. > > > > > > - Use x86_match_cpu() in intel_cqm_init() and make sure we grab the > > > hotplug lock to prevent races as pointed out by Andi Kleen in > > > PATCH 08/11. > > > > > > - Delete a stale comment in commit message of PATCH 10/11. > > > > No support for a modular driver? > > I didn't include support for that because none of the other x86 pmu > drivers are buildable as modules. Is there a reason for that?
Not really, the rapl driver could easily be a module, and I think there were osme patches to make the uncore driver a module.
> It's not clear to me that it would be a worthwhile change to make this > buildable as a module, since that would require a Kconfig entry and the > user would be required to make a decision regarding whether or not they > want to build CQM support. > > It's much simpler to just build it in and enable it based on > CONFIG_PERF_EVENTS + CONFIG_INTEL_CPU. In fact, that's one of the things > I've always liked about the pmu drivers, if I move to a new machine and > turn on PERF_EVENTS the correct drivers will be run.
Some people worry about the memory footprint of all that.. That said, I think we can do without the Kconfig stuff if we allow CONFIG_PERF_EVENTS to be a tristate, in that case M would build everything that can be a module as a module and keep the rest builtin.
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