Ian Rogers 53df2b9344 libsymbols kallsyms: Parse using io api ... 'perf record' will call kallsyms__parse 4 times during startup and process megabytes of data. This changes kallsyms__parse to use the io library rather than fgets to improve performance of the user code by over 8%. Before: Running 'internals/kallsyms-parse' benchmark: Average kallsyms__parse took: 103.988 ms (+- 0.203 ms) After: Running 'internals/kallsyms-parse' benchmark: Average kallsyms__parse took: 95.571 ms (+- 0.006 ms) For a workload like: $ perf record /bin/true Run under 'perf record -e cycles:u -g' the time goes from: Before 30.10% 1.67% perf perf [.] kallsyms__parse After 25.55% 20.04% perf perf [.] kallsyms__parse So a little under 5% of the start-up time is removed. A lot of what remains is on the kernel side, but caching kallsyms within perf would at least impact memory footprint. Committer notes: The internal/kallsyms-parse bench is run using: [root@five ~]# perf bench internals kallsyms-parse # Running 'internals/kallsyms-parse' benchmark: Average kallsyms__parse took: 80.381 ms (+- 0.115 ms) [root@five ~]# And this pre-existing test uses these routines to parse kallsyms and then compare with the info obtained from the matching ELF symtab: [root@five ~]# perf test vmlinux 1: vmlinux symtab matches kallsyms : Ok [root@five ~]# Also we can't remove hex2u64() in this patch as this breaks the build: /usr/bin/ld: /tmp/build/perf/perf-in.o: in function `modules__parse': /home/acme/git/perf/tools/perf/util/symbol.c:607: undefined reference to `hex2u64' /usr/bin/ld: /home/acme/git/perf/tools/perf/util/symbol.c:607: undefined reference to `hex2u64' /usr/bin/ld: /tmp/build/perf/perf-in.o: in function `dso__load_perf_map': /home/acme/git/perf/tools/perf/util/symbol.c:1477: undefined reference to `hex2u64' /usr/bin/ld: /home/acme/git/perf/tools/perf/util/symbol.c:1483: undefined reference to `hex2u64' collect2: error: ld returned 1 exit status Leave it there, move it in the next patch. Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> 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/20200501221315.54715-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>		2020-05-05 16:35:32 -03:00
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kallsyms.c	libsymbols kallsyms: Parse using io api	2020-05-05 16:35:32 -03:00
kallsyms.h	tools perf: Move from sane_ctype.h obtained from git to the Linux's original	2019-06-25 21:02:47 -03:00