lwn.git/tools/perf/util/parse-events.c, branch docs-6.8-2

perf pmu: Lazily compute default config

2023-10-17T19:40:50+00:00

The default config is computed during creation of the PMU and may do things like scanning sysfs, when the PMU may just be used as part of scanning. Change default_config to perf_event_attr_init_default, a callback that is used when a default config needs initializing. This avoids holding onto the memory for a perf_event_attr and copying. On a tigerlake laptop running the pmu-scan benchmark: Before: Running 'internals/pmu-scan' benchmark: Computing performance of sysfs PMU event scan for 100 times Average core PMU scanning took: 28.780 usec (+- 0.503 usec) Average PMU scanning took: 283.480 usec (+- 18.471 usec) Number of openat syscalls: 30,227 After: Running 'internals/pmu-scan' benchmark: Computing performance of sysfs PMU event scan for 100 times Average core PMU scanning took: 27.880 usec (+- 0.169 usec) Average PMU scanning took: 245.260 usec (+- 15.758 usec) Number of openat syscalls: 28,914 Over 3 runs it is a nearly 12% reduction in execution time and a 4.3% of openat calls. Signed-off-by: Ian Rogers Reviewed-by: Adrian Hunter Cc: Ravi Bangoria Cc: James Clark Cc: Suzuki K Poulose Cc: Yang Jihong Cc: Will Deacon Cc: Leo Yan Cc: Mike Leach Cc: Jing Zhang Cc: Kajol Jain Cc: Thomas Richter Cc: Kan Liang Cc: John Garry Cc: linux-arm-kernel@lists.infradead.org Cc: coresight@lists.linaro.org Link: https://lore.kernel.org/r/20231012175645.1849503-8-irogers@google.com Signed-off-by: Namhyung Kim

perf parse-events: Fix unlikely memory leak when cloning terms

2023-10-12T17:01:57+00:00

Add missing free on an error path as detected by clang-tidy. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Ravi Bangoria Cc: Nick Desaulniers Cc: Yang Jihong Cc: Huacai Chen Cc: Nathan Chancellor Cc: Kan Liang Cc: llvm@lists.linux.dev Cc: Ming Wang Cc: Tom Rix Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20231009183920.200859-16-irogers@google.com Signed-off-by: Namhyung Kim

perf parse-events: Introduce 'struct parse_events_terms'

2023-09-11T13:26:36+00:00

parse_events_terms() existed in function names but was passed a 'struct list_head'. As many parse_events functions take an evsel_config list as well as a parse_event_term list, and the naming head_terms and head_config is inconsistent, there's a potential to switch the lists and get errors. Introduce a 'struct parse_events_terms', that just wraps a list_head, to avoid this. Add the regular init/exit functions and transition the code to use them. Reviewed-by: James Clark Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rob Herring Link: https://lore.kernel.org/r/20230901233949.2930562-6-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Copy fewer term lists

2023-09-11T13:26:36+00:00

When trying to add events to multiple PMUs the term list is copied first as adding the event will rewrite the event's name term into the sysfs and/or json encoding terms (see perf_pmu__check_alias). Change the parse events add API so the passed in term list is const, then copy the list when modification is necessary. Reviewed-by: James Clark Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rob Herring Link: https://lore.kernel.org/r/20230901233949.2930562-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Tidy up str parameter

2023-09-11T13:26:36+00:00

Add a const and rename str to event_name. Reviewed-by: James Clark Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rob Herring Link: https://lore.kernel.org/r/20230901233949.2930562-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Remove unnecessary __maybe_unused

2023-09-11T13:26:36+00:00

The parameter head_terms is always used in get_config_terms. Reviewed-by: James Clark Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rob Herring Link: https://lore.kernel.org/r/20230901233949.2930562-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Fixes relating to no_value terms

2023-09-02T11:12:15+00:00

A term may have no value in which case it is assumed to have a value of 1. It doesn't just apply to alias/event terms so change the parse_events_term__to_strbuf assert. Commit 99e7138eb7897aa0 ("perf tools: Fail on using multiple bits long terms without value") made it so that no_value terms could only be for a single bit. Prior to commit 64199ae4b8a3 ("perf parse-events: Fix propagation of term's no_value when cloning") this missed a test case where config1 had no_value. Fixes: 64199ae4b8a36038 ("perf parse-events: Fix propagation of term's no_value when cloning") Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rob Herring Link: https://lore.kernel.org/r/20230901233949.2930562-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Fix propagation of term's no_value when cloning

2023-08-31T19:24:59+00:00

The no_value field in 'struct parse_events_term' indicates that the val variable isn't used, the case for an event name. Cloning wasn't propagating this, making cloned event name terms appearing to have a constant assinged to them. Working around the bug would check for a value of 1 assigned to value, but then this meant a user value of 1 couldn't be differentiated causing the value to be lost in debug printing and perf list. The change fixes the cloning and updates the "val.num ==/!= 1" tests to use no_value instead. To better check the no_value is set appropriately parameter comments are added for constant values. This found that no_value wasn't set correctly in parse_events_multi_pmu_add, which matters now that no_value is used to indicate an event name. Fixes: 7a6e91644708d514 ("perf parse-events: Make common term list to strbuf helper") Fixes: 99e7138eb7897aa0 ("perf tools: Fail on using multiple bits long terms without value") Signed-off-by: Ian Rogers Tested-by: Kan Liang Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rob Herring Link: https://lore.kernel.org/r/20230831071421.2201358-4-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Name the two term enums

2023-08-31T19:24:55+00:00

Name the enums used by 'struct parse_events_term' to parse_events__term_val_type and parse_events__term_type. This allows greater compile time error checking. Fix -Wswitch related issues by explicitly listing all enum values prior to default. Add config_term_name to safely look up a parse_events__term_type name, bounds checking the array access first. Add documentation to 'struct parse_events_terms' and reorder to save space. Signed-off-by: Ian Rogers Tested-by: Kan Liang Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rob Herring Link: https://lore.kernel.org/r/20230831071421.2201358-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Make common term list to strbuf helper

2023-08-31T02:03:03+00:00

A term list is turned into a string for debug output and for the str value in the alias. Add a helper to do this based on existing code, but then fix for situations like events being identified. Use strbuf to manage the dynamic memory allocation and remove the 256 byte limit. Use in various places the string of the term list is required. Before: $ sudo perf stat -vv -e inst_retired.any true Using CPUID GenuineIntel-6-8D-1 intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch Attempting to add event pmu 'cpu' with 'inst_retired.any,' that may result in non-fatal errors After aliases, add event pmu 'cpu' with 'event,period,' that may result in non-fatal errors inst_retired.any -> cpu/inst_retired.any/ ... After: $ sudo perf stat -vv -e inst_retired.any true Using CPUID GenuineIntel-6-8D-1 intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch Attempt to add: cpu/inst_retired.any/ ..after resolving event: cpu/event=0xc0,period=0x1e8483/ inst_retired.any -> cpu/event=0xc0,period=0x1e8483/ ... Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20230830070753.1821629-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo