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From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>, Kajol Jain <kjain@linux.ibm.com>,
	Andi Kleen <andi@firstfloor.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-perf-users@vger.kernel.org
Subject: perf probe + uprobes missing events
Date: Mon, 6 Apr 2020 11:53:56 -0300	[thread overview]
Message-ID: <20200406145356.GA32649@kernel.org> (raw)

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

             reply	other threads:[~2020-04-06 14:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-06 14:53 Arnaldo Carvalho de Melo [this message]
2020-04-06 14:54 ` perf probe + uprobes missing events Arnaldo Carvalho de Melo
2020-04-07 12:39 ` Masami Hiramatsu
2020-04-08  3:14   ` Masami Hiramatsu

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