Re: [PATCH 5/7] perf tools: Introduce perf_target__strerror()

[Arnaldo Carvalho de Melo <acme@ghostprotocols.net>]

Em Mon, May 07, 2012 at 02:09:02PM +0900, Namhyung Kim escreveu:
> The perf_target__strerror() sets @buf to a string that
> describes the (perf_target-specific) error condition
> that is passed via @errnum.
> 
> This is similar to strerror_r() and does same thing if
> @errnum has a standard errno value.

This has a problem: why should I be warned when I do, as root:

# perf top -u acme

It warns me that "UID switch overriding SYSTEM", yeah, right that is
what I asked, no need to tell me that :-)

So what is missing in this case is that top starts with system_wide set,
not from the command line.

I.e. if I had asked for:

# perf top --system_wide --user acme

Ok, the warning would make sense.

So just special case this in the top case, I think, like the patch
below, ack?

I'll fold this into this patch and add a [ committer note: ... ]

Ack?

- Arnaldo

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index a2518fc..780791f 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1257,7 +1257,16 @@ int cmd_top(int argc, const char **argv, const char *prefix __used)
 	setup_browser(false);
 
 	status = perf_target__validate(&top.target);
-	if (status != PERF_ERRNO_TARGET__SUCCESS) {
+	if (status != PERF_ERRNO_TARGET__SUCCESS &&
+	    status != PERF_ERRNO_TARGET__PID_OVERRIDE_SYSTEM &&
+	    status != PERF_ERRNO_TARGET__UID_OVERRIDE_SYSTEM) {
+		/*
+ 		 * Top doesn't provide an explicit way to ask for system wide
+ 		 * profiling, it is the default.
+ 		 *
+ 		 * So we shouldn't warn the user when he/she asks for --pid or
+ 		 * --uid.
+ 		 */
 		perf_target__strerror(&top.target, status, errbuf, BUFSIZ);
 		ui__warning("%s", errbuf);
 	}