Messages in this thread | | | From | Namhyung Kim <> | Subject | Re: perf: Add support for full Intel event lists v5 | Date | Mon, 09 Jun 2014 14:56:34 +0900 |
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On Fri, 30 May 2014 14:50:06 -0700, Andi Kleen wrote: > [v2: Review feedback addressed and some minor improvements] > [v3: More review feedback addressed and handle test failures better. > Ported to latest tip/core.] > [v4: Addressed Namhyung's feedback] > [v5: Rebase to latest tree. Minor description update.] > > perf has high level events which are useful in many cases. However > there are some tuning situations where low level events in the CPU > are needed. Traditionally this required specifying the event in > raw form (very awkward) or using non standard frontends > like ocperf or patching in libpfm. > > Intel CPUs can have very large event files (Haswell has ~336 core events, > much more if you add uncore or all the offcore combinations), which is too > large to describe through the kernel interface. It would require tying up > significant amounts of unswappable memory for this. > > oprofile always had separate event list files that were maintained by > the CPU vendors. The oprofile events were shipped with the tool. > The Intel events get updated regularly, for example to add references > to the specification updates or add new events. > > Unfortunately oprofile usually did not keep up with these updates, > so the events in oprofile were often out of date. In addition > it ties up quite a bit of disk space, mostly for CPUs you don't have. > > This patch kit implements another mechanism that avoids these problems. > Intel releases the event lists for CPUs in a standardized JSON format > on a download server. > > I implemented an automatic downloader to get the event file for the > current CPU. The events are stored in ~/.cache/pmu-events. > Then perf adds a parser that converts the JSON format into perf event > aliases, which then can be used directly as any other perf event. > > The parsing is done using a simple existing JSON library. > > The events are still abstracted for perf, but the abstraction mechanism is > through the downloaded file instead of through the kernel. > > The JSON format and perf parser has some minor Intelisms, but they > are simple and small and optional. It's easy to extend, so it would be > possible to use it for other CPUs too, add different pmu attributes, and > add new download sites to the downloader tool. > > Currently only core events are supported, uncore may come at a later > point. No kernel changes, all code in perf user tools only. > > Some of the parser files are partially shared with separate event parser > library and are thus 2-clause BSD licensed.
So I played with this patchset for a little while, and it's mostly good and I left comments for each patch I have concerns. With that change,
Acked-by: Namhyung Kim <namhyung@kernel.org>
Hopefully other vendors will add support for their cpus too.
Thanks, Namhyung
> > Patches also available from > git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc perf/json > > Example output: > > % perf download > Downloading models file > Downloading readme.txt > 2014-03-05 10:39:33 URL:https://download.01.org/perfmon/readme.txt [10320/10320] -> "readme.txt" [1] > 2014-03-05 10:39:34 URL:https://download.01.org/perfmon/mapfile.csv [1207/1207] -> "mapfile.csv" [1] > Downloading events file > % perf list > ... > br_inst_exec.all_branches [Speculative and retired > branches] > br_inst_exec.all_conditional [Speculative and retired > macro-conditional > branches] > br_inst_exec.all_direct_jmp [Speculative and retired > macro-unconditional > branches excluding > calls and indirects] > ... 333 more new events ... > > % perf stat -e br_inst_exec.all_direct_jmp true > > Performance counter stats for 'true': > > 6,817 cpu/br_inst_exec.all_direct_jmp/ > > 0.003503212 seconds time elapsed > > One nice feature is that a pointer to the specification update is now > included in the description, which will hopefully clear up many problems: > > % perf list > ... > mem_load_uops_l3_hit_retired.xsnp_hit [Retired load uops which > data sources were L3 > and cross-core snoop > hits in on-pkg core > cache. Supports address > when precise. Spec > update: HSM26, HSM30 > (Precise event)] > ... > > > -Andi
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