Messages in this thread | | | From | Namhyung Kim <> | Subject | Re: [PATCH 05/14] perf tools: Introduce new 'ftrace' tool | Date | Thu, 25 Apr 2013 18:51:46 +0900 |
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On Thu, 25 Apr 2013 11:09:56 +0200, Jiri Olsa wrote: > On Thu, Apr 25, 2013 at 03:06:37PM +0900, Namhyung Kim wrote: >> On Wed, 24 Apr 2013 16:09:18 +0200, Jiri Olsa wrote: >> > On Tue, Apr 23, 2013 at 05:31:03PM +0900, Namhyung Kim wrote: >> >> From: Namhyung Kim <namhyung.kim@lge.com> >> >> +out: >> >> + put_tracing_file(file); >> >> + return ret; >> >> +} >> >> + >> >> +static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) >> >> +{ >> >> + if (write_tracing_file("tracing_on", "0") < 0) >> >> + return -1; >> >> + >> >> + if (write_tracing_file("current_tracer", "nop") < 0) >> >> + return -1; >> >> + >> >> + if (write_tracing_file("set_ftrace_pid", " ") < 0) >> >> + return -1; >> > >> > I think we want to reset set_ftrace_pid file as well >> > probably to -1.. >> > >> > if I'm tracing command with this file having wrong CPU(s) >> > I dont get any data.. >> >> Not sure I understood what you mean exactly. > > ugh, sry.. I wrote set_ftrace_pid when I actually meant tracing_cpumask ;-)
Okay. :)
> >> >> Do you mean it should be changed to >> >> if (write_tracing_file("set_ftrace_pid", "-1") < 0) >> >> ? It seems it's the right thing to do for compatibility. > > > looks like it's enough only to open it with O_TRUNC, > so I guess whatever minimal goes write_tracing_file
Yeah, but I can see below from trace-cmd code.
trace-cmd/trace-record.c:
/* * Older kernels required "-1" to disable pid */ if (ret < 0 && !strlen(pid)) ret = write(fd, "-1", 2);
Could you clarify this, Steve?
Thanks, Namhyung
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