linux/tools/perf
Vincent Whitchurch 1beaef29c3 perf bench mem: Always memset source before memcpy
For memcpy, the source pages are memset to zero only when --cycles is
used.  This leads to wildly different results with or without --cycles,
since all sources pages are likely to be mapped to the same zero page
without explicit writes.

Before this fix:

$ export cmd="./perf stat -e LLC-loads -- ./perf bench \
  mem memcpy -s 1024MB -l 100 -f default"
$ $cmd

         2,935,826      LLC-loads
       3.821677452 seconds time elapsed

$ $cmd --cycles

       217,533,436      LLC-loads
       8.616725985 seconds time elapsed

After this fix:

$ $cmd

       214,459,686      LLC-loads
       8.674301124 seconds time elapsed

$ $cmd --cycles

       214,758,651      LLC-loads
       8.644480006 seconds time elapsed

Fixes: 47b5757bac ("perf bench mem: Move boilerplate memory allocation to the infrastructure")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.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: kernel@axis.com
Link: http://lore.kernel.org/lkml/20200810133404.30829-1-vincent.whitchurch@axis.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-08-13 09:34:26 -03:00
..
arch perf tools changes for v5.9 2020-08-10 19:21:38 -07:00
bench perf bench mem: Always memset source before memcpy 2020-08-13 09:34:26 -03:00
Documentation perf data: Add support to store time of day in CTF data conversion 2020-08-06 09:43:37 -03:00
examples/bpf Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-01-28 16:02:33 -08:00
include/bpf perf bpf: Remove bpf/ subdir from bpf.h headers used to build bpf events 2020-02-18 10:13:28 -03:00
jvmti perf jvmti: Remove redundant jitdump line table entries 2020-05-29 16:51:38 -03:00
pmu-events Merge remote-tracking branch 'torvalds/master' into perf/core 2020-08-03 09:37:31 -03:00
python treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 407 2019-06-05 17:37:14 +02:00
scripts perf scripts python: exported-sql-viewer.py: Fix time chart call tree 2020-07-03 08:19:52 -03:00
tests Merge remote-tracking branch 'torvalds/master' into perf/core 2020-08-03 09:37:31 -03:00
trace perf trace beauty: Use the autogenerated protocol family table 2020-08-12 08:43:51 -03:00
ui Merge remote-tracking branch 'torvalds/master' into perf/core 2020-07-08 13:49:15 -03:00
util perf data: Add support to store time of day in CTF data conversion 2020-08-06 09:43:37 -03:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
Build
builtin-annotate.c perf evsel: Rename perf_evsel__resort*() to evsel__resort*() 2020-05-28 10:03:24 -03:00
builtin-bench.c perf bench: Add benchmark of find_next_bit 2020-07-31 09:32:11 -03:00
builtin-buildid-cache.c perf session: Return error code for perf_session__new() function on failure 2019-09-20 15:58:11 -03:00
builtin-buildid-list.c perf session: Return error code for perf_session__new() function on failure 2019-09-20 15:58:11 -03:00
builtin-c2c.c perf evlist: Fix the class prefix for 'struct evlist' sample_type methods 2020-06-22 16:28:09 -03:00
builtin-config.c perf tools: Remove util.h from where it is not needed 2019-09-20 09:19:20 -03:00
builtin-data.c perf data: Add support to store time of day in CTF data conversion 2020-08-06 09:43:37 -03:00
builtin-diff.c perf evsel: Rename perf_evsel__is_*() to evsel__is*() 2020-05-05 16:35:31 -03:00
builtin-evlist.c perf evsel: Rename perf_evsel__fprintf() to evsel__fprintf() 2020-05-28 10:03:24 -03:00
builtin-ftrace.c perf ftrace: Detect workload failure 2020-05-28 10:03:27 -03:00
builtin-help.c perf debug: Remove needless include directives from debug.h 2019-08-31 19:10:19 -03:00
builtin-inject.c perf inject jit: Remove //anon mmap events 2020-07-08 13:51:12 -03:00
builtin-kallsyms.c perf dsos: Move the dsos struct and its methods to separate source files 2019-08-31 22:24:10 -03:00
builtin-kmem.c perf kmem: Pass additional arguments to 'perf record' 2020-07-10 09:37:55 -03:00
builtin-kvm.c perf evlist: Fix the class prefix for 'struct evlist' 'add' evsel methods 2020-06-22 16:28:09 -03:00
builtin-list.c perf list: Add metrics to command line usage 2020-05-28 10:03:28 -03:00
builtin-lock.c perf lock: Rename perf_evsel__*() operating on 'struct evsel *' to evsel__*() 2020-05-05 16:35:31 -03:00
builtin-mem.c perf c2c: Fix 'perf c2c record -e list' to show the default events used 2020-05-28 10:03:25 -03:00
builtin-probe.c perf probe: Do not show the skipped events 2020-05-28 10:03:24 -03:00
builtin-record.c perf record: Skip side-band event setup if HAVE_LIBBPF_SUPPORT is not set 2020-08-07 09:27:03 -03:00
builtin-report.c perf evlist: Fix the class prefix for 'struct evlist' branch_type methods 2020-06-22 16:28:10 -03:00
builtin-sched.c perf sched: Prefer sched_waking event when it exists 2020-08-13 09:34:26 -03:00
builtin-script.c perf script: Add 'tod' field to display time of day 2020-08-06 09:45:23 -03:00
builtin-stat.c perf stat: Introduce --control fd:ctl-fd[,ack-fd] options 2020-08-04 08:48:58 -03:00
builtin-timechart.c perf tools: Replace zero-length array with flexible-array 2020-05-28 10:03:27 -03:00
builtin-top.c perf evlist: Fix the class prefix for 'struct evlist' 'add' evsel methods 2020-06-22 16:28:09 -03:00
builtin-trace.c perf record: Extend -D,--delay option with -1 value 2020-08-04 08:50:04 -03:00
builtin-version.c perf symbols: Move mem_info and branch_info out of symbol.h 2019-08-31 22:27:48 -03:00
builtin.h perf tools: Remove needless util.h include from builtin.h 2019-08-28 17:19:34 -03:00
check-headers.sh perf trace beauty: Use the autogenerated protocol family table 2020-08-12 08:43:51 -03:00
command-list.txt
CREDITS
design.txt perf tools: Support CAP_PERFMON capability 2020-04-16 12:19:08 -03:00
Makefile tools: Let O= makes handle a relative path with -C option 2020-03-06 17:08:28 -03:00
Makefile.config perf build: Fix error message when asking for -fsanitize=address without required libraries 2020-06-18 10:34:31 -03:00
Makefile.perf perf trace beauty: Use the autogenerated protocol family table 2020-08-12 08:43:51 -03:00
MANIFEST libperf: Move to tools/lib/perf 2020-01-06 11:46:09 -03:00
perf-archive.sh
perf-completion.sh
perf-read-vdso.c
perf-sys.h perf tools: Make usage of test_attr__* optional for perf-sys.h 2019-10-31 21:38:41 +01:00
perf-with-kcore.sh Merge branch 'x86/cpu' into perf/core, to pick up dependent changes 2019-06-17 12:29:16 +02:00
perf.c libperf: Merge libperf_set_print() into libperf_init() 2019-09-25 09:51:49 -03:00
perf.h perf time-utils: Adopt rdclock() from perf.h 2019-08-29 17:38:32 -03:00