From: Greg KH <gregkh@linuxfoundation.org>
To: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>,
roman.sudarikov@linux.intel.com, peterz@infradead.org,
mingo@redhat.com, acme@kernel.org, mark.rutland@arm.com,
alexander.shishkin@linux.intel.com, jolsa@redhat.com,
namhyung@kernel.org, linux-kernel@vger.kernel.org,
eranian@google.com, bgregg@netflix.com,
alexander.antonov@intel.com
Subject: Re: [PATCH v5 3/3] perf x86: Exposing an Uncore unit to PMON for Intel Xeon® server platform
Date: Tue, 11 Feb 2020 12:14:27 -0800 [thread overview]
Message-ID: <20200211201427.GA1975593@kroah.com> (raw)
In-Reply-To: <25dca8dd-c52d-676d-ffe4-90f3a6ddc915@linux.intel.com>
On Tue, Feb 11, 2020 at 02:59:21PM -0500, Liang, Kan wrote:
>
>
> On 2/11/2020 1:57 PM, Greg KH wrote:
> > On Tue, Feb 11, 2020 at 10:42:00AM -0800, Andi Kleen wrote:
> > > On Tue, Feb 11, 2020 at 09:15:44AM -0800, Greg KH wrote:
> > > > On Tue, Feb 11, 2020 at 07:15:49PM +0300, roman.sudarikov@linux.intel.com wrote:
> > > > > +static ssize_t skx_iio_mapping_show(struct device *dev,
> > > > > + struct device_attribute *attr, char *buf)
> > > > > +{
> > > > > + struct pmu *pmu = dev_get_drvdata(dev);
> > > > > + struct intel_uncore_pmu *uncore_pmu =
> > > > > + container_of(pmu, struct intel_uncore_pmu, pmu);
> > > > > +
> > > > > + struct dev_ext_attribute *ea =
> > > > > + container_of(attr, struct dev_ext_attribute, attr);
> > > > > + long die = (long)ea->var;
> > > > > +
> > > > > + return sprintf(buf, "0000:%02x\n", skx_iio_stack(uncore_pmu, die));
> > > >
> > > > If "0000:" is always the "prefix" of the output of this file, why have
> > > > it at all as you always know it is there?
>
>
> I think Roman only test with BIOS configured as single-segment. So he
> hard-code the segment# here.
>
> I'm not sure if Roman can do some test with multiple-segment BIOS. If not, I
> think we should at least print a warning here.
>
> > > >
> > > > What is ever going to cause that to change?
> > >
> > > I think it's just to make it a complete PCI address.
> >
> > Is that what this really is? If so, it's not a "complete" pci address,
> > is it? If it is, use the real pci address please.
>
> I think we don't need a complete PCI address here. The attr is to disclose
> the mapping information between die and PCI BUS. Segment:BUS should be good
> enough.
"good enough" for today, but note that you can not change the format of
the data in the file in the future, you would have to create a new file.
So I suggest at least try to future-proof it as much as possible if you
_know_ this could change.
Just use the full pci address, there's no reason not to, otherwise it's
just confusing.
thanks,
greg k-h
next prev parent reply other threads:[~2020-02-11 20:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 16:15 [PATCH v5 0/3] perf x86: Exposing IO stack to IO PMON mapping through sysfs roman.sudarikov
2020-02-11 16:15 ` [PATCH v5 1/3] perf x86: Infrastructure for exposing an Uncore unit to PMON mapping roman.sudarikov
2020-02-11 16:15 ` [PATCH v5 2/3] perf x86: topology max dies for whole system roman.sudarikov
2020-02-11 16:15 ` [PATCH v5 3/3] perf x86: Exposing an Uncore unit to PMON for Intel Xeon® server platform roman.sudarikov
2020-02-11 17:15 ` Greg KH
2020-02-11 18:42 ` Andi Kleen
2020-02-11 18:57 ` Greg KH
2020-02-11 19:59 ` Liang, Kan
2020-02-11 20:14 ` Greg KH [this message]
2020-02-12 17:31 ` Sudarikov, Roman
2020-02-12 20:58 ` Liang, Kan
2020-02-12 22:56 ` Greg KH
2020-02-13 12:36 ` Sudarikov, Roman
2020-02-13 13:08 ` Greg KH
2020-02-11 17:18 ` Greg KH
2020-02-11 20:09 ` Liang, Kan
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