kernel.git/tools/perf/util/parse-events.l, branch linux-6.18.y

perf parse-events: Fix parsing of >30kb event strings

2025-10-03T22:06:19Z

Metrics may generate many particularly uncore event references. The resulting event string may then be >32kb. The parse events lex is using "%option reject" which stores backtracking state in a buffer sized at roughtly 30kb. If the event string is larger than this then a buffer overflow and typically a crash happens. The need for "%option reject" was for BPF events which were removed in commit 3d6dfae88917 ("perf parse-events: Remove BPF event support"). As "%option reject" is both a memory and performance cost let's remove it and fix the parsing case for event strings being over ~30kb. Whilst cleaning up "%option reject" make the header files accurately reflect functions used in the code and tidy up not requiring yywrap. Measuring on the "PMU JSON event tests" a modest reduction of 0.41% user time and 0.27% max resident size was observed. More importantly this change fixes parsing large metrics and event strings. 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 Signed-off-by: Arnaldo Carvalho de Melo

perf record: Add ratio-to-prev term

2025-10-03T19:49:51Z

Provide ratio-to-prev term which allows the user to set the event sample period of two events corresponding to a desired ratio. If using on an Intel x86 platform with Auto Counter Reload support, also set corresponding event's config2 attribute with a bitmask which counters to reset and which counters to sample if the desired ratio is met or exceeded. On other platforms, only the sample period is affected by the ratio-to-prev term. Reviewed-by: Ian Rogers Signed-off-by: Thomas Falcon Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Dapeng Mi Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Add 'X' modifier to exclude an event from being regrouped

2025-09-12T18:53:32Z

The function parse_events__sort_events_and_fix_groups is needed to fix uncore events like: ``` $ perf stat -e '{data_read,data_write}' ... ``` so that the multiple uncore PMUs have a group each of data_read and data_write events. The same function will perform architecture sorting and group fixing, in particular for Intel topdown/perf-metric events. Grouping multiple perf metric events together causes perf_event_open to fail as the group can only support one. This means command lines like: ``` $ perf stat -e 'slots,slots' ... ``` fail as the slots events are forced into a group together to try to satisfy the perf-metric event constraints. As the user may know better than parse_events__sort_events_and_fix_groups add a 'X' modifier to skip its regrouping behavior. This allows the following to succeed rather than fail on the second slots event being opened: ``` $ perf stat -e 'slots,slots:X' -a sleep 1 Performance counter stats for 'system wide': 6,834,154,071 cpu_core/slots/ (50.13%) 5,548,629,453 cpu_core/slots/X (49.87%) 1.002634606 seconds time elapsed ``` Closes: https://lore.kernel.org/lkml/20250822082233.1850417-1-dapeng1.mi@linux.intel.com/ Reported-by: Dapeng Mi Reported-by: Xudong Hao Reviewed-by: Dapeng Mi Signed-off-by: Ian Rogers Tested-by: Dapeng Mi Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Greg Kroah-Hartman Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Falcon Cc: Yoshihiro Furudera Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Remove non-json software events

2025-07-26T23:31:43Z

Remove the hard coded encodings from parse-events. This has the consequence that software events are matched using the sysfs/json priority, will be case insensitive and will be wildcarded across PMUs. As there were software and hardware types in the parsing code, the removal means software vs hardware logic can be removed and hardware assumed. Now the perf json provides detailed descriptions of software events, remove the previous listing support that didn't contain event descriptions. When globbing is required for the "sw" option in perf list, use string PMU globbing as was done previously for the tool PMU. The output of `perf list sw` command changed like this. Before: List of pre-defined events (to be used in -e or -M): alignment-faults [Software event] bpf-output [Software event] cgroup-switches [Software event] context-switches OR cs [Software event] cpu-clock [Software event] cpu-migrations OR migrations [Software event] dummy [Software event] emulation-faults [Software event] major-faults [Software event] minor-faults [Software event] page-faults OR faults [Software event] task-clock [Software event] After: List of pre-defined events (to be used in -e or -M): software: alignment-faults [Number of kernel handled memory alignment faults. Unit: software] bpf-output [An event used by BPF programs to write to the perf ring buffer. Unit: software] cgroup-switches [Number of context switches to a task in a different cgroup. Unit: software] context-switches [Number of context switches [This event is an alias of cs]. Unit: software] cpu-clock [Per-CPU high-resolution timer based event. Unit: software] cpu-migrations [Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software] cs [Number of context switches [This event is an alias of context-switches]. Unit: software] dummy [A placeholder event that doesn't count anything. Unit: software] ... Signed-off-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/r/20250725185202.68671-4-irogers@google.com Signed-off-by: Namhyung Kim

perf parse-events: Add "cpu" term to set the CPU an event is recorded on

2025-05-12T17:23:19Z

The -C option allows the CPUs for a list of events to be specified but its not possible to set the CPU for a single event. Add a term to allow this. The term isn't a general CPU list due to ',' already being a special character in event parsing instead multiple cpu= terms may be provided and they will be merged/unioned together. An example of mixing different types of events counted on different CPUs: ``` $ perf stat -A -C 0,4-5,8 -e "instructions/cpu=0/,l1d-misses/cpu=4,cpu=5/,inst_retired.any/cpu=8/,cycles" -a sleep 0.1 Performance counter stats for 'system wide': CPU0 6,979,225 instructions/cpu=0/ # 0.89 insn per cycle CPU4 75,138 cpu/l1d-misses/ CPU5 1,418,939 cpu/l1d-misses/ CPU8 797,553 cpu/inst_retired.any,cpu=8/ CPU0 7,845,302 cycles CPU4 6,546,859 cycles CPU5 185,915,438 cycles CPU8 2,065,668 cycles 0.112449242 seconds time elapsed ``` Committer testing: root@number:~# grep -m1 "model name" /proc/cpuinfo model name : AMD Ryzen 9 9950X3D 16-Core Processor root@number:~# perf stat -A -e "instructions/cpu=0/,instructions,l1d-misses/cpu=4,cpu=5/,cycles" -a sleep 0.1 Performance counter stats for 'system wide': CPU0 2,398,351 instructions/cpu=0/ # 0.44 insn per cycle CPU0 2,398,152 instructions # 0.44 insn per cycle CPU1 1,265,634 instructions # 0.49 insn per cycle CPU2 606,087 instructions # 0.50 insn per cycle CPU3 4,025,752 instructions # 0.52 insn per cycle CPU4 4,236,810 instructions # 0.53 insn per cycle CPU5 3,984,832 instructions # 0.66 insn per cycle CPU6 434,132 instructions # 0.44 insn per cycle CPU7 65,752 instructions # 0.41 insn per cycle CPU8 459,083 instructions # 0.48 insn per cycle CPU9 6,464,161 instructions # 1.31 insn per cycle root@number:~# perf stat -e "instructions/cpu=0/,instructions,l1d-misses/cpu=4,cpu=5/,cycles" -a sleep 0. Performance counter stats for 'system wide': 144,822 instructions/cpu=0/ # 0.03 insn per cycle 4,666,114 instructions # 0.93 insn per cycle 2,583 l1d-misses 4,993,633 cycles 0.000868512 seconds time elapsed root@number:~# Signed-off-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Tested-by: Kan Liang Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Dominique Martinet Cc: Greg Kroah-Hartman Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Weilin Wang Cc: Yicong Yang Link: https://lore.kernel.org/r/20250403194337.40202-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Tidy name token matching

2025-02-21T06:35:10Z

Prior to commit 70c90e4a6b2f ("perf parse-events: Avoid scanning PMUs before parsing") names (generally event names) excluded hyphen (minus) symbols as the formation of legacy names with hyphens was handled in the yacc code. That commit allowed hyphens supposedly making name_minus unnecessary. However, changing name_minus to name has issues in the term config tokens as then name ends up having priority over numbers and name allows matching numbers since commit 5ceb57990bf4 ("perf parse: Allow tracepoint names to start with digits "). It is also permissable for a name to match with a colon (':') in it when its in a config term list. To address this rename name_minus to term_name, make the pattern match name's except for the colon, add number matching into the config term region with a higher priority than name matching. This addresses an inconsistency and allows greater matching for names inside of term lists, for example, they may start with a number. Rename name_tag to quoted_name and update comments and helper functions to avoid str detecting quoted strings which was already done by the lexer. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250109175401.161340-1-irogers@google.com Signed-off-by: Namhyung Kim

perf tools: Add aux-action config term

2024-12-18T19:24:32Z

Add a new common config term "aux-action" to use for configuring AUX area trace pause / resume. The value is a string that will be parsed in a subsequent patch. Reviewed-by: Andi Kleen Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Namhyung Kim Link: https://lore.kernel.org/r/20241216070244.14450-3-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tool_pmu: Factor tool events into their own PMU

2024-10-11T06:40:32Z

Rather than treat tool events as a special kind of event, create a tool only PMU where the events/aliases match the existing duration_time, user_time and system_time events. Remove special parsing and printing support for the tool events, but add function calls for when PMU functions are called on a tool_pmu. Move the tool PMU code in evsel into tool_pmu.c to better encapsulate the tool event behavior in that file. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Link: https://lore.kernel.org/r/20241002032016.333748-5-irogers@google.com Signed-off-by: Namhyung Kim

perf parse-events: Add a retirement latency modifier

2024-08-12T21:15:27Z

Retirement latency is a separate sampled count used on newer Intel CPUs. Reviewed-by: Namhyung Kim Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Caleb Biggers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Perry Taylor Cc: Peter Zijlstra Cc: Samantha Alt Link: https://lore.kernel.org/r/20240720062102.444578-2-weilin.wang@intel.com Signed-off-by: Weilin Wang Signed-off-by: Arnaldo Carvalho de Melo

Revert "perf parse-events: Prefer sysfs/JSON hardware events over legacy"

2024-05-26T11:41:34Z

This reverts commit 617824a7f0f73e4de325cf8add58e55b28c12493. This made a simple 'perf record -e cycles:pp make -j199' stop working on the Ampere ARM64 system Linus uses to test ARM64 kernels, as discussed at length in the threads in the Link tags below. The fix provided by Ian wasn't acceptable and work to fix this will take time we don't have at this point, so lets revert this and work on it on the next devel cycle. Reported-by: Linus Torvalds Cc: Adrian Hunter Cc: Bhaskar Chowdhury Cc: Ethan Adams Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Thomas Gleixner Cc: Thomas Richter Cc: Tycho Andersen Cc: Yang Jihong Link: https://lore.kernel.org/lkml/CAHk-=wi5Ri=yR2jBVk-4HzTzpoAWOgstr1LEvg_-OXtJvXXJOA@mail.gmail.com Link: https://lore.kernel.org/lkml/CAHk-=wiWvtFyedDNpoV7a8Fq_FpbB+F5KmWK2xPY3QoYseOf_A@mail.gmail.com Signed-off-by: Arnaldo Carvalho de Melo