Re: [PATCH v2 5/6] perf stat: Enable iiostat mode for x86 platforms

[Alexander Antonov]

On 1/14/2021 6:39 AM, Namhyung Kim wrote:
> On Wed, Jan 13, 2021 at 9:08 PM Alexander Antonov
> <alexander.antonov@xxxxxxxxxxxxxxx> wrote:
> > On 1/6/2021 12:02 PM, Namhyung Kim wrote:
> > > On Wed, Dec 23, 2020 at 10:03 PM Alexander Antonov
> > > <alexander.antonov@xxxxxxxxxxxxxxx> wrote:
> > > > This functionality is based on recently introduced sysfs attributes
> > > > for Intel® Xeon® Scalable processor family (code name Skylake-SP):
> > > > Commit bb42b3d39781 ("perf/x86/intel/uncore: Expose an Uncore unit to
> > > > IIO PMON mapping")
> > > >
> > > > Mode is intended to provide four I/O performance metrics in MB per each
> > > > IIO stack:
> > > >    - Inbound Read: I/O devices below IIO stack read from the host memory
> > > >    - Inbound Write: I/O devices below IIO stack write to the host memory
> > > >    - Outbound Read: CPU reads from I/O devices below IIO stack
> > > >    - Outbound Write: CPU writes to I/O devices below IIO stack
> > > >
> > > > Each metric requiries only one IIO event which increments at every 4B
> > > > transfer in corresponding direction. The formulas to compute metrics
> > > > are generic:
> > > >       #EventCount * 4B / (1024 * 1024)
> > > Hmm.. maybe we can do this with JSON metrics, no?
> > Do you mean to add metrics to *-metrics.json file?
> > Looks like it's possible but in this case JSON file should be updated
> > for each
> > new enabled platform and calculations will be the same.
> > I would prefer to leave it as is because perf will work without changing of
> > userspace part once IIO sysfs attributes are added for new platforms.
> OK.
>
> > > > Signed-off-by: Alexander Antonov <alexander.antonov@xxxxxxxxxxxxxxx>
> > > > ---
> [SNIP]
> > > > diff --git a/tools/perf/perf-iiostat.sh b/tools/perf/perf-iiostat.sh
> > > > new file mode 100644
> > > > index 000000000000..2c5168d2550b
> > > > --- /dev/null
> > > > +++ b/tools/perf/perf-iiostat.sh
> > > > @@ -0,0 +1,12 @@
> > > > +#!/bin/bash
> > > > +# SPDX-License-Identifier: GPL-2.0
> > > > +# perf iiostat
> > > > +# Alexander Antonov <alexander.antonov@xxxxxxxxxxxxxxx>
> > > > +
> > > > +if [[ "$1" == "show" ]] || [[ "$1" =~ ([a-f0-9A-F]{1,}):([a-f0-9A-F]{1,2})(,)? ]]; then
> > > > +        DELIMITER="="
> > > > +else
> > > > +        DELIMITER=" "
> > > > +fi
> > > > +
> > > > +perf stat --iiostat$DELIMITER$*
> > > Why is this needed?
> > >
> > > Thanks,
> > > Namhyung
> > Arnaldo raised question relates to format of 'perf stat --iiostat'
> > subcommand
> > and explained how it can be changed to 'perf iiostat' through the aliases
> > mechanism in perf.
> Yeah, I know that.  What I'm asking is the DELIMITER part.
>
> Thanks,
> Namhyung
I'm using DELIMITER to resolve two different cases for format of iiostat 
command:
The first one is the command with an option for iiostat mode, for example:
'perf iiostat show' which should be converted to 'perf stat 
--iiostat=show' or
'perf iiostat 0000:ae,0000:5d' to 'perf stat --iiostat=0000:ae,0000:5d'.
The second is the command without any option for iiostat: 'perf iiostat 
-I 1000'
should be converted to 'perf stat --iiostat -I 1000'.

Thanks,
Alexander