Messages in this thread | | | Subject | Re: [PATCH 5/9] perf: Adding sysfs group format attribute for pmu device | From | Peter Zijlstra <> | Date | Fri, 27 Jan 2012 22:19:42 +0100 |
| |
On Fri, 2012-01-27 at 13:08 -0800, Corey Ashford wrote: > s an example, the IBM PowerEN processor has roughly 20 different PMU's > on it. Some of those PMU's are quite complex and divide their events up > into subsets, each with different fields. For example, some events may > have a PID matching field, and others may have an bus number matching > field, or matching mode field, etc. The fields are different widths, > and may overlap in the config/1/2 space. > > It seems that there are two approaches you could take: > > 1) Keep your format, but allow the fields to overlap in the bit space. > For example: > > "/sys/...<dev>/format/event" contains "config:0-7" > "/sys/...<dev>/format/pidmatch" contains "config:8-15" > "/sys/...<dev>/format/busmatch" contains "config:8-13" > > Note that busmatch overlaps pidmatch > > 2) Create event groups that have their overlapping config space > separated out: > > "/sys/...<dev>/format/event" contains "config:0-7" > > "/sys/...<dev>.1/format/pidmatch" contains "config:8-15" > > "/sys/...<dev>.2/format/busmatch" contains "config:8-13" > > > Notice the .1 and .2 on the <dev>. > > This might help the user understand which fields go together. I'm not > sold on the .1 syntax... you could do it as <dev>.<event-group-name>/ or > <dev>/<event-group-name>/... or whatever seems to make the most sense > and is relatively easy to implement and use.
Why try and stuff those 20 in a single driver? Have 20 drivers and each their own format/ hierarchy.
| |