From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 33FFB30FF26; Wed, 8 Apr 2026 17:18:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775668684; cv=none; b=sOhV6/7ZqHrdcN/aVQsr6LxMddr6UjBbTOnCy9vW5MBvstcm6XtUEP0xzWUV7OJ/jx/9H0RRjqtTNYaX01/pGWvn3rw/CIuLlELOE+hZXjlBI9hO7h+KS9wh4yw5r4XnoKuVifuAdIghuVBFYwlK9ac/+ykugZCCsY3R4ud2WtQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775668684; c=relaxed/simple; bh=vMveKG0CT6yaQBp5cdSyC0GlyBfV4qOBC+znHP6soho=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=TIAvmqaQCEHjXuTTyl646OeR2fLwIejU+C7wAPzw4sgDS+LEYav3WtXcUsghcJlsT2Tan17A8ctn4kkKtTLN6PFe7zthsoPEjz+2W4052mLqvY3PcaySjJM7zMA13nxlJ9SowoIqohADVpHMESWHj2knmMzM6/IevrH0dyf6OBg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=a6UM4ZfM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="a6UM4ZfM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57935C19425; Wed, 8 Apr 2026 17:18:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775668683; bh=vMveKG0CT6yaQBp5cdSyC0GlyBfV4qOBC+znHP6soho=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=a6UM4ZfMQYP2/zqACgibCFAgoY7qW6T+CNSXX3z+Sp0dx1ThiAV04zje8L1mYLZ+9 uRW9IB/vv+UnxL3O0OZ4izWhcKysnSVY/3v0qwoE5gk/YQM1yWx1fALmULz31SvZo4 DZ5y2oEBc0viUUERolZSBivjKSucFV+AYL30k15q+l/I/P82p1RgSEGWYiFhZFctiB 3cKa90p/v6DWUGYWT9DF23FFpqiCze9i2zUt+uWKacofOHOPMvoWQxo+qXEQgyQXsM q+3HfP3B2h1kYBvjutveDW0WlmrTbzGqa6pW/gF4q74XecRd85baGZBXcOJ2Rkeitn tjvetz7l7cRBg== Message-ID: <36cf0fc5ee3a4476b0a70536d212278a9ee4d380.camel@kernel.org> Subject: Re: [PATCH v2 1/2] tracing/hist: rebuild full_name on each hist_field_name() call From: Tom Zanussi To: Steven Rostedt Cc: Pengpeng Hou , mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Date: Wed, 08 Apr 2026 12:18:02 -0500 In-Reply-To: <20260408122514.60bbfd61@gandalf.local.home> References: <20260401112224.85582-1-pengpeng@iscas.ac.cn> <20260407210502.102e5d37@gandalf.local.home> <20260408122514.60bbfd61@gandalf.local.home> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.3-0ubuntu1.1 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2026-04-08 at 12:25 -0400, Steven Rostedt wrote: > On Wed, 08 Apr 2026 10:58:06 -0500 > Tom Zanussi wrote: >=20 > Hi Tom, >=20 > > ->system is set when using fully-qualified variable names. For=C2=A0= =20 > > instance: > >=20 > > echo 'hist:keys=3Dpid:ts0=3Dcommon_timestamp.usecs' >> sys/kernel/debug= /tracing/events/sched/sched_waking/trigger > > echo 'hist:keys=3Dpid:ts0=3Dcommon_timestamp.usecs' >> /sys/kernel/debu= g/tracing/events/sched/sched_wakeup/trigger > > echo 'hist:keys=3Dnext_pid:lat0=3Dcommon_timestamp.usecs-sched.sched_wa= king.$ts0:lat1=3Dcommon_timestamp.usecs-sched.sched_wakeup.$ts0' >> /sys/ke= rnel/debug/tracing/events/sched/sched_switch/trigger > > echo 'hist:keys=3Dnext_pid:vals=3D$lat0,$lat1' >> /sys/kernel/debug/tra= cing/events/sched/sched_switch/trigger > >=20 > > Here, the sched_switch trigger would error out if the unqualified $ts0 > > variables were used instead of the fully-qualified ones because there's > > no way to distinguish which $ts0 was meant. > >=20 >=20 > Yep I see that now. I never had a need to use it before, but I probably > should implement this in libtracefs to be safe. >=20 > We should definitely add a selftest that tests this. There's one case tha= t > does use it but it doesn't use multiple ones. We should add a test that > does so. >=20 > trigger-multi-actions-accept.tc has the system, but it's not needed here. >=20 > We should also have a test to test the output of theses lines. Yeah, definitely. I can try adding this as a test.. Tom >=20 > -- Steve