perf probe + uprobes missing events
From: Arnaldo Carvalho de Melo
Date: Mon Apr 06 2020 - 10:54:05 EST
Hi Masami,
I'm trying to use 'perf probe' to debug 'perf test', but I'm not
getting repeatable results, take a look:
I'm trying to figure out which expresssions are _really_ being tested
byu the 'perf test expr' testcase, so I added a probe to the
expr__parse() routine, asking for the expr string to be printed:
[root@five ~]# perf probe -x ~/bin/perf -L expr__parse
<expr__parse@/home/acme/git/perf/tools/perf/util/expr.c:0>
0 int expr__parse(double *final_val, struct expr_parse_ctx *ctx, const char *expr, int runtime)
1 {
2 return __expr__parse(final_val, ctx, expr, EXPR_PARSE, runtime) ? -1 : 0;
3 }
static bool
already_seen(const char *val, const char *one, const char **other,
[root@five ~]#
[root@five ~]# perf probe -x ~/bin/perf expr__parse expr:string
Target program is compiled without optimization. Skipping prologue.
Probe on address 0x5cb11b to force probing at the function entry.
Added new event:
probe_perf:expr__parse (on expr__parse in /home/acme/bin/perf with expr:string)
You can now use it in all perf tools, such as:
perf record -e probe_perf:expr__parse -aR sleep 1
[root@five ~]#
[root@five ~]# perf trace -e probe_perf:expr_* perf test -F expr
7: Simple expression parser : Ok
0.000 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1+1")
0.015 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "FOO+BAR")
0.018 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "(BAR/2)%2")
0.020 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1 - -4")
0.023 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "(FOO-1)*2 + (BAR/2)%2 - -4")
0.026 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1-1 | 1")
0.029 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1-1 & 1")
0.031 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "min(1,2) + 1")
0.034 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "max(1,2) + 1")
0.036 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1+1 if 3*4 else 0")
0.039 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "FOO/0")
0.041 :2994175/2994175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "BAR/")
[root@five ~]# perf trace -e probe_perf:expr_* perf test -F expr
7: Simple expression parser : Ok
0.000 perf/2996042 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1+1")
0.021 perf/2996042 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "FOO+BAR")
0.025 perf/2996042 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "(BAR/2)%2")
0.029 perf/2996042 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1 - -4")
0.033 perf/2996042 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "(FOO-1)*2 + (BAR/2)%2 - -4")
0.041 perf/2996042 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1-1 | 1")
0.044 perf/2996042 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1-1 & 1")
[root@five ~]# perf trace -e probe_perf:expr_* perf test -F expr
7: Simple expression parser : Ok
0.000 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1+1")
0.020 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "FOO+BAR")
0.025 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "(BAR/2)%2")
0.029 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1 - -4")
0.032 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "(FOO-1)*2 + (BAR/2)%2 - -4")
0.037 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1-1 | 1")
0.040 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1-1 & 1")
0.043 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "min(1,2) + 1")
0.046 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "max(1,2) + 1")
0.049 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1+1 if 3*4 else 0")
0.053 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "FOO/0")
0.056 perf/2996416 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "BAR/")
[root@five ~]# perf trace -e probe_perf:expr_* perf test -F expr
7: Simple expression parser : Ok
[root@five ~]# perf trace -e probe_perf:expr_* perf test -F expr
7: Simple expression parser : Ok
[root@five ~]# perf trace -e probe_perf:expr_* perf test -F expr
7: Simple expression parser : Ok
[root@five ~]# perf trace -e probe_perf:expr_* perf test -F expr
7: Simple expression parser : Ok
[root@five ~]# perf trace -e probe_perf:expr_* perf test -F expr
7: Simple expression parser : Ok
0.000 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1+1")
0.014 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "FOO+BAR")
0.017 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "(BAR/2)%2")
0.021 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1 - -4")
0.024 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "(FOO-1)*2 + (BAR/2)%2 - -4")
0.030 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1-1 | 1")
0.032 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1-1 & 1")
0.035 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "min(1,2) + 1")
0.038 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "max(1,2) + 1")
0.040 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "1+1 if 3*4 else 0")
0.044 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "FOO/0")
0.046 :2998175/2998175 probe_perf:expr__parse(__probe_ip: 6074674, expr_string: "BAR/")
[root@five ~]#
Do you have any idea why that happens?
- Arnaldo