From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D3F373C76A0; Wed, 26 Aug 2026 18:58:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787770705; cv=none; b=iiYZFaVwez5pTvD8q8WfSa27STheQ0vhYw6e93+YvqWYi6YopzPJiiYTNXi0Lxc1/6i1vhbsJh9fysdcSqoNT7MRTq6U6VQb70DoC/K8/OzP2XVjYR/E+tJSjIM3f6uYoLZz0G4Vwb0KZ0XmSffVJy8eWPnXbIK4QXiGV50/se0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787770705; c=relaxed/simple; bh=7yVu7NGuF4jj3EeqtJX7hFsbveOdchtEl9yumj3rivg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=V/2ddXBYcYjHDE5zPDVrD8gFsUOeTvw+Z0+6E1afYnQ8xH4mHprhp/t49RZCtIDrnrtrVQF5cjYEL3Ci7Znhr9o2fbwX0MtVsXS6b4/zOwIextHsXCeYih4IZl4jO5aQcaqenpi+nnUeKwljMQiUBcjFr+E1ep9XghfDDUNE4sE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Jw/vs888; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Jw/vs888" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 861E11F000E9; Wed, 26 Aug 2026 18:58:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787770697; bh=mjcItGCHrnB/ioZeYCgC7spPCZuPgfw0z2OYhAXp9qg=; h=From:To:Cc:Subject:Date; b=Jw/vs888lHxf3+rtuYMReuArz/1AQYySXX1nB2WyrQyV1H/NWVg7H9HyoLvvU5HEh 7x2W2XlRFiz5Mg+9U5C/d0qPcxw1G+IJu/zucEgQXkJWsp5FUMZR/czmTsDtYAvqOO DzuPsaBn/k6X2ThGsqUW7VgxEQLVw59lYuMz4UQWBTXMY0MmGm1fnfsYTuUsp0D9LD IVSdNwTLEc97YsaB9XjVjSQ0QWd24Ed/0QhSe1q//yCuI/He5A58UViq8b3Yrtinqj r3OPn4KGZksq4U3CAlN1L85xSRyCJq1iLv93B2vomXlQeVz5Ak/cn3Y8uNtTp0wTCM sREUEzHQRSJBQ== From: Namhyung Kim To: Arnaldo Carvalho de Melo Cc: Ian Rogers , Jiri Olsa , Adrian Hunter , James Clark , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Steven Rostedt , Masami Hiramatsu Subject: [PATCH] perf ftrace latency: Do not read trace files when BPF is used Date: Wed, 26 Aug 2026 11:58:15 -0700 Message-ID: <20260826185815.280451-1-namhyung@kernel.org> X-Mailer: git-send-email 2.55.0.897.gb25b4bd76c-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit I've realized that it didn't set up the tracing files when BPF is used so poll() just returns immediately. It ends up with calling poll() unnecessarily in a loop. BPF still needs the loop to wait for the target process exiting or a signal from users. Let's sleep for 1 msec and check that. Cc: Steven Rostedt Cc: Masami Hiramatsu Signed-off-by: Namhyung Kim --- tools/perf/builtin-ftrace.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 4f881a40c311ae52..e61b9de11e1e41c7 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -1146,6 +1146,11 @@ static int __cmd_latency(struct perf_ftrace *ftrace) line[0] = '\0'; while (!done) { + if (ftrace->target.use_bpf) { + usleep(1000); + continue; + } + if (poll(&pollfd, 1, -1) < 0) break; -- 2.55.0.897.gb25b4bd76c-goog