From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) (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 51A2B481A8E; Wed, 1 Jul 2026 13:11:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782911471; cv=none; b=pmwUMemPD6IwIQ5B4F856IlEbG9HD6SjvaSb50svMvKDTpSn/Pa1cUa8h5Ayw6+bhFm0xIp+DsIIJthfCDiCAdtDI+Zj6PikOeFPJ7PKlWVuO9/ef7KMrLQ/u1/Ta67sdpCXLgXHwhgBMyug7tttc67FA4iovncHtUQKDDy7rW4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782911471; c=relaxed/simple; bh=wrUn1pkW77N46zYgZ2lhvLL6ZsiJ0dm7nBBozpj51pk=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=DihC73Aa/27k4R1XCkWP6qeNbJtTbYZEJJhdFXv/5aakXuTaq0udtvZJ7oRRH2uTJTGQbUov/BMxM9z8i7F2BV3f1erhxwPaZrZrNQKd7rFSyijqhwtHSOZE6N6qjl6Ktpu/xkpAUpex5IKmpaFIO5cbJ8Yac/e3+M8bHbFwaC8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf16.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 77E748B135; Wed, 1 Jul 2026 13:11:08 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf16.hostedemail.com (Postfix) with ESMTPA id 26FAE2000F; Wed, 1 Jul 2026 13:11:06 +0000 (UTC) Date: Wed, 1 Jul 2026 09:11:07 -0400 From: Steven Rostedt To: Tomas Glozar Cc: Valentin Schneider , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Masami Hiramatsu , Mathieu Desnoyers , Costa Shulyupin , Crystal Wood , John Kacur , Ivan Pravdin , Jonathan Corbet Subject: Re: [RFC PATCH v2 4/4] rtla/osnoise: Leverage IPI event filters when tracing a subset of CPUs Message-ID: <20260701091107.2943a03b@gandalf.local.home> In-Reply-To: References: <20260617131803.2988989-1-vschneid@redhat.com> <20260617131803.2988989-5-vschneid@redhat.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 26FAE2000F X-Stat-Signature: bhg3zocy1g9ia9hft6qa96raqd8kxfub X-Rspamd-Server: rspamout07 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX18i7tg9x8gydDY/oYQcHrwJQzjOStGAI7s= X-HE-Tag: 1782911466-294695 X-HE-Meta: U2FsdGVkX19ouVEwxASN2S+id23wKChO6hYBjfhEVovlB05Cc6ySh0l9GKczh3DUFk+cTwkbDZMAFVkcsp8CZsxOLGBvdCesmE4eE8q9fMe38hPjjG8yus6fPHe4rCyXHhwpptCMNOt5HbgvTVrV0gHg7IOng3oW4o/iUuPkyYBg5LPlz0QWQ/hLidpE9RISya2UIXdTBhCPaf7RxRAuyDsZrI2XKyU/CacNUM9QbB0SbA+XcOFMPm4zDEurh8dEFENlVPHjeU2JM8KqNcyMatIg+uaU/bJr4HmbdKqszj8ISrU4Mx+icLwlvBvp1FEpYE4YsBswIU1UZa1qX2v16qgwzxlt18Wp On Wed, 1 Jul 2026 08:45:40 +0200 Tomas Glozar wrote: > I double-checked that and you are correct that the docstring says so, > but it's an error in the docstring. According to the manpage, it > returns the number of bytes written (i.e. positive on success, not > zero) [1]: Note, the man page is considered the source of "truth". > > "RETURN VALUE > ... > tracefs_event_file_write() and tracefs_event_file_append() returns > *the number of bytes written to the system/event file* or negative on > error." > > The code agrees as well: in tracefs_event_file_write() there's the > wrong docstring (likely copied from another function) [2]: > > /* > * tracefs_event_file_write - write to an event file > * ... > * Return 0 on success, and -1 on error. Ug, that's a bug and needs to be fixed. Thanks for catching this. I need to spend some time to catch up on the user side of tracing. There's a few new bugzillas and patches I need to apply. -- Steve > */ > int tracefs_event_file_write(struct tracefs_instance *instance, > const char *system, const char *event, > const char *file, const char *str) > { > .... > ret = tracefs_instance_file_write(instance, path, str); > free(path); > return ret; > }