From: Steven Rostedt <rostedt@goodmis.org>
To: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Cc: Linux Trace Devel <linux-trace-devel@vger.kernel.org>
Subject: Move "load_plugins" out of the opening code
Date: Tue, 19 Jan 2021 09:59:39 -0500 [thread overview]
Message-ID: <20210119095939.6f307c4d@gandalf.local.home> (raw)
Tzvetomir,
From bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=211255
It was reported that:
$ trace-cmd report -N -r funcgraph_exit trace.dat 2>/dev/null | grep funcgraph_exit | wc -l
11645
$ trace-cmd report -N -F funcgraph_exit -r funcgraph_exit trace.dat 2>/dev/null | grep funcgraph_exit | wc -l
24826
Where the first should have been as big as the second. The problem with the
above is really that "-N" does not stop the ftrace function event plugins
from being loaded.
Looking at this further, I think it's a mistake to have the plugins loaded
at opening time.
We should have a new function for the library:
int tracecmd_load_plugins(struct tracecmd_handle *handle, int flags);
And this should be called after read_trace_header() in trace-read.c.
We can still have tracecmd_open_head() call this, as the "open_head" is
basically a "do everything" function.
This will allow us to remove the global "tracecmd_disable_plugins" and
"tracecmd_disable_sys_plugins" variables and use the flags input instead.
With the '-N' option, we should probably just skip calling it regardless.
The below patch was just a POC, to see if there was any side-effects for
this. But it didn't have a return value or flags, which should be added for
the final version.
-- Steve
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 3e67dd61..11bf8e5d 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -3247,11 +3247,6 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd)
if (!handle->pevent)
goto failed_read;
- /* register default ftrace functions first */
- tracecmd_ftrace_overrides(handle, &handle->finfo);
-
- handle->plugin_list = trace_load_plugins(handle->pevent);
-
tep_set_file_bigendian(handle->pevent, buf[0]);
tep_set_local_bigendian(handle->pevent, tracecmd_host_bigendian());
@@ -3344,6 +3339,13 @@ struct tracecmd_input *tracecmd_open(const char *file)
return tracecmd_open_fd(fd);
}
+void tracecmd_load_plugins(struct tracecmd_input *handle)
+{
+ /* register default ftrace functions first */
+ tracecmd_ftrace_overrides(handle, &handle->finfo);
+ handle->plugin_list = trace_load_plugins(handle->pevent);
+}
+
/**
* tracecmd_open_head - create a tracecmd_handle from a given file, read
* and parse only the trace headers from the file
diff --git a/tracecmd/trace-read.c b/tracecmd/trace-read.c
index d07f4efe..a79bf0aa 100644
--- a/tracecmd/trace-read.c
+++ b/tracecmd/trace-read.c
@@ -1768,10 +1768,14 @@ void trace_report (int argc, char **argv)
die("Wakeup tracing can only be done on a single input file");
list_for_each_entry(inputs, &input_files, list) {
+ void tracecmd_load_plugins(struct tracecmd_input *handle);
handle = read_trace_header(inputs->file);
if (!handle)
die("error reading header for %s", inputs->file);
+ if (!tracecmd_disable_plugins)
+ tracecmd_load_plugins(handle);
+
/* If used with instances, top instance will have no tag */
add_handle(handle, multi_inputs ? inputs->file : NULL);
next reply other threads:[~2021-01-19 18:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-19 14:59 Steven Rostedt [this message]
2021-02-04 11:04 ` Move "load_plugins" out of the opening code Tzvetomir Stoyanov
2021-02-04 14:17 ` Steven Rostedt
2021-02-04 14:31 ` Steven Rostedt
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