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On a CPU like skylakex an uncore_iio_0 PMU may alias with
uncore_iio_free_running_0. The latter PMU doesn't support fc_mask as a
parameter and so pmu_config_term fails. Typically parse_events_add_pmu
is called in a loop where if one alias succeeds errors are ignored,
however, if multiple errors occur parse_events__handle_error will
currently give a WARN_ONCE.
This change removes the WARN_ONCE in parse_events__handle_error and
makes it a pr_debug. It adds verbose messages to parse_events_add_pmu
warning that non-fatal errors may occur, while giving details on the pmu
and config terms for useful context. pmu_config_term is altered so the
failing term and pmu are present in the case of the 'unknown term' error
which makes spotting the free_running case more straightforward.
Before:
$ perf --debug verbose=3 stat -M llc_misses.pcie_read sleep 1
Using CPUID GenuineIntel-6-55-4
metric expr unc_iio_data_req_of_cpu.mem_read.part0 + unc_iio_data_req_of_cpu.mem_read.part1 + unc_iio_data_req_of_cpu.mem_read.part2 + unc_iio_data_req_of_cpu.mem_read.part3 for LLC_MISSES.PCIE_READ
found event unc_iio_data_req_of_cpu.mem_read.part0
found event unc_iio_data_req_of_cpu.mem_read.part1
found event unc_iio_data_req_of_cpu.mem_read.part2
found event unc_iio_data_req_of_cpu.mem_read.part3
metric expr unc_iio_data_req_of_cpu.mem_read.part0 + unc_iio_data_req_of_cpu.mem_read.part1 + unc_iio_data_req_of_cpu.mem_read.part2 + unc_iio_data_req_of_cpu.mem_read.part3 for LLC_MISSES.PCIE_READ
found event unc_iio_data_req_of_cpu.mem_read.part0
found event unc_iio_data_req_of_cpu.mem_read.part1
found event unc_iio_data_req_of_cpu.mem_read.part2
found event unc_iio_data_req_of_cpu.mem_read.part3
adding {unc_iio_data_req_of_cpu.mem_read.part0,unc_iio_data_req_of_cpu.mem_read.part1,unc_iio_data_req_of_cpu.mem_read.part2,unc_iio_data_req_of_cpu.mem_read.part3}:W,{unc_iio_data_req_of_cpu.mem_read.part0,unc_iio_data_req_of_cpu.mem_read.part1,unc_iio_data_req_of_cpu.mem_read.part2,unc_iio_data_req_of_cpu.mem_read.part3}:W
intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
WARNING: multiple event parsing errors
...
Invalid event/parameter 'fc_mask'
...
After:
$ perf --debug verbose=3 stat -M llc_misses.pcie_read sleep 1
Using CPUID GenuineIntel-6-55-4
metric expr unc_iio_data_req_of_cpu.mem_read.part0 + unc_iio_data_req_of_cpu.mem_read.part1 + unc_iio_data_req_of_cpu.mem_read.part2 + unc_iio_data_req_of_cpu.mem_read.part3 for LLC_MISSES.PCIE_READ
found event unc_iio_data_req_of_cpu.mem_read.part0
found event unc_iio_data_req_of_cpu.mem_read.part1
found event unc_iio_data_req_of_cpu.mem_read.part2
found event unc_iio_data_req_of_cpu.mem_read.part3
metric expr unc_iio_data_req_of_cpu.mem_read.part0 + unc_iio_data_req_of_cpu.mem_read.part1 + unc_iio_data_req_of_cpu.mem_read.part2 + unc_iio_data_req_of_cpu.mem_read.part3 for LLC_MISSES.PCIE_READ
found event unc_iio_data_req_of_cpu.mem_read.part0
found event unc_iio_data_req_of_cpu.mem_read.part1
found event unc_iio_data_req_of_cpu.mem_read.part2
found event unc_iio_data_req_of_cpu.mem_read.part3
adding {unc_iio_data_req_of_cpu.mem_read.part0,unc_iio_data_req_of_cpu.mem_read.part1,unc_iio_data_req_of_cpu.mem_read.part2,unc_iio_data_req_of_cpu.mem_read.part3}:W,{unc_iio_data_req_of_cpu.mem_read.part0,unc_iio_data_req_of_cpu.mem_read.part1,unc_iio_data_req_of_cpu.mem_read.part2,unc_iio_data_req_of_cpu.mem_read.part3}:W
intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
Attempting to add event pmu 'uncore_iio_free_running_5' with 'unc_iio_data_req_of_cpu.mem_read.part0,' that may result in non-fatal errors
After aliases, add event pmu 'uncore_iio_free_running_5' with 'fc_mask,ch_mask,umask,event,' that may result in non-fatal errors
Attempting to add event pmu 'uncore_iio_free_running_3' with 'unc_iio_data_req_of_cpu.mem_read.part0,' that may result in non-fatal errors
After aliases, add event pmu 'uncore_iio_free_running_3' with 'fc_mask,ch_mask,umask,event,' that may result in non-fatal errors
Attempting to add event pmu 'uncore_iio_free_running_1' with 'unc_iio_data_req_of_cpu.mem_read.part0,' that may result in non-fatal errors
After aliases, add event pmu 'uncore_iio_free_running_1' with 'fc_mask,ch_mask,umask,event,' that may result in non-fatal errors
Multiple errors dropping message: unknown term 'fc_mask' for pmu 'uncore_iio_free_running_3' (valid terms: event,umask,config,config1,config2,name,period,percore)
...
So before you see a 'WARNING: multiple event parsing errors' and
'Invalid event/parameter'. After you see 'Attempting... that may result
in non-fatal errors' then 'Multiple errors...' with details that
'fc_mask' wasn't known to a free running counter. While not completely
clean, this makes it clearer that an error hasn't really occurred.
v2. addresses review feedback from Jiri Olsa <jolsa@redhat.com>.
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/lkml/20200513220635.54700-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.