From: Namhyung Kim <namhyung@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>, Jiri Olsa <jolsa@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
Andi Kleen <ak@linux.intel.com>, Ian Rogers <irogers@google.com>,
Alexey Alexandrov <aalexand@google.com>
Subject: [PATCH] perf record: Disallow -c and -F option at the same time
Date: Fri, 2 Apr 2021 18:40:20 +0900 [thread overview]
Message-ID: <20210402094020.28164-1-namhyung@kernel.org> (raw)
It's confusing which one is effective when the both options are given.
The current code happens to use -c in this case but users might not be
aware of it. We can change it to complain about that instead of
relying on the implicit priority.
Before:
$ perf record -c 111111 -F 99 true
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.031 MB perf.data (8 samples) ]
$ perf evlist -F
cycles: sample_period=111111
After:
$ perf record -c 111111 -F 99 true
cannot set frequency and period at the same time
So this change can break existing usages, but I think it's rare to
have both options and it'd be better changing them.
Suggested-by: Alexey Alexandrov <aalexand@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/util/record.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c
index f99852d54b14..43e5b563dee8 100644
--- a/tools/perf/util/record.c
+++ b/tools/perf/util/record.c
@@ -157,9 +157,15 @@ static int get_max_rate(unsigned int *rate)
static int record_opts__config_freq(struct record_opts *opts)
{
bool user_freq = opts->user_freq != UINT_MAX;
+ bool user_interval = opts->user_interval != ULLONG_MAX;
unsigned int max_rate;
- if (opts->user_interval != ULLONG_MAX)
+ if (user_interval && user_freq) {
+ pr_err("cannot set frequency and period at the same time\n");
+ return -1;
+ }
+
+ if (user_interval)
opts->default_interval = opts->user_interval;
if (user_freq)
opts->freq = opts->user_freq;
--
2.31.0.208.g409f899ff0-goog
next reply other threads:[~2021-04-02 9:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-02 9:40 Namhyung Kim [this message]
2021-04-02 13:37 ` [PATCH] perf record: Disallow -c and -F option at the same time Arnaldo Carvalho de Melo
[not found] ` <CANtFmmo6Wq_u=D89hkfmS8yMtKhk+6pm_4YawpO-6MvS_4noaw@mail.gmail.com>
2021-04-03 17:13 ` Arnaldo Carvalho de Melo
[not found] ` <CANtFmmqeBPW7XHAvphw9YpGy74b3T-jfzg1op+9ZyU=YLDLjDg@mail.gmail.com>
2021-05-03 21:32 ` Namhyung Kim
2021-05-04 12:38 ` Arnaldo Carvalho de Melo
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