From: Arnaldo Carvalho de Melo acme@redhat.com
[ Upstream commit 1da7e0022784b0e05b49bf73521fa2cc4633af85 ]
When introducing the possibility for selecting if the common prefix to options such as the waitid ones, i.e. all 'waitid' options start with 'W', so, to make it make it more compact if configured to suppress it, 'perf trace' will do so, other examples include mmap's PROT_ prefix for its 'prot' argument, etc, which, when showing the syscall argument name ends up producing duplicated info that clutters the screen, i.e.:
# perf trace -e mmap --max-events 2 sleep 1 0.000 ( 0.014 ms): sleep/20886 mmap(len: 112595, prot: PROT_READ, flags: MAP_PRIVATE, fd: 3) = 0x7f3e986d2000 0.041 ( 0.005 ms): sleep/20886 mmap(len: 8192, prot: PROT_READ|PROT_WRITE, flags: MAP_PRIVATE|MAP_ANONYMOUS) = 0x7f3e986d0000 #
So it is possible to suppress that and make it more compact by having this in your ~/.perfconfig:
# cat ~/.perfconfig [trace] show_prefix = no #
# perf trace -e mmap --max-events 2 sleep 1 0.000 ( 0.014 ms): sleep/8009 mmap(len: 112595, prot: READ, flags: PRIVATE, fd: 3) = 0x7ff2373de000 0.040 ( 0.005 ms): sleep/8009 mmap(len: 8192, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS) = 0x7ff2373dc000 #
To have it look more like strace's output, we instead want to suppress the arg name and show the prefix, so use:
# cat ~/.perfconfig [trace] show_prefix = yes show_arg_names = no # # perf trace -e mmap --max-events 2 sleep 1 0.000 ( 0.006 ms): sleep/15513 mmap(NULL, 112595, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f7a9b6d3000 0.020 ( 0.002 ms): sleep/15513 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS) = 0x7f7a9b6d1000 #
When this logic was introduced a bug came with it when processing the waitid 'option' arg that ended up expecting 3 strings when just two were being provided, fix it.
Cc: Adrian Hunter adrian.hunter@intel.com Cc: Jiri Olsa jolsa@kernel.org Cc: Luis Cláudio Gonçalves lclaudio@redhat.com Cc: Namhyung Kim namhyung@kernel.org Cc: Wang Nan wangnan0@huawei.com Fixes: c65c83ffe904 ("perf trace: Allow asking for not suppressing common string prefixes") Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/trace/beauty/waitid_options.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/trace/beauty/waitid_options.c b/tools/perf/trace/beauty/waitid_options.c index 6897fab40dcc..d4d10b33ba0e 100644 --- a/tools/perf/trace/beauty/waitid_options.c +++ b/tools/perf/trace/beauty/waitid_options.c @@ -11,7 +11,7 @@ static size_t syscall_arg__scnprintf_waitid_options(char *bf, size_t size,
#define P_OPTION(n) \ if (options & W##n) { \ - printed += scnprintf(bf + printed, size - printed, "%s%s%s", printed ? "|" : "", show_prefix ? prefix : #n); \ + printed += scnprintf(bf + printed, size - printed, "%s%s%s", printed ? "|" : "", show_prefix ? prefix : "", #n); \ options &= ~W##n; \ }