Messages in this thread | | | Date | Fri, 18 Apr 2014 12:53:54 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v2 4/4] perf/x86/uncore: modularize Intel uncore driver |
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* Yan, Zheng <zheng.z.yan@intel.com> wrote:
> This patch adds support for building Intel uncore driver as module. > It adds clean-up code and config option for the Intel uncore driver > > Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com> > --- > Changes since v1: > move config option to "General setup/Kernel Performance Events and Counters" > > arch/x86/kernel/cpu/Makefile | 3 +- > arch/x86/kernel/cpu/perf_event_intel_uncore.c | 48 ++++++++++++++++++++++++--- > init/Kconfig | 10 ++++++ > 3 files changed, 56 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile > index 7fd54f0..5d3da70 100644 > --- a/arch/x86/kernel/cpu/Makefile > +++ b/arch/x86/kernel/cpu/Makefile > @@ -36,7 +36,8 @@ obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd_iommu.o > endif > obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_p6.o perf_event_knc.o perf_event_p4.o > obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_lbr.o perf_event_intel_ds.o perf_event_intel.o > -obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_uncore.o perf_event_intel_rapl.o > +obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_rapl.o > +obj-$(CONFIG_PERF_X86_INTEL_UNCORE) += perf_event_intel_uncore.o > endif > > > diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c > index 618d502..fd5e883 100644 > --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c > +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
So I'm not willing to apply this patch until the documentation of perf_event_intel_uncore.c is improved. Right now the file starts without a single comment (!). Just lines after lines of code, without any explanation what it does, what its scope is, etc.
How should even a knowledgable user know about what it's all about?
That problem percolates to the Kconfig entry as well:
> --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1502,6 +1502,16 @@ config PERF_EVENTS > > Say Y if unsure. > > +config PERF_X86_INTEL_UNCORE > + default y > + tristate "Intel uncore performance monitoring support" > + depends on PERF_EVENTS && CPU_SUP_INTEL && PCI > + help > + This option allows kernel to access the Uncore performance > + monitoring units of Intel processors. > + > + Say Y if unsure.
Firstly, it should probably not be 'default y'.
Secondly, the description is essentially non-existent. What does the hardware do? Why should users care about uncore PMUs?
This needs to be fixed before we can make this modular.
Thanks,
Ingo
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