From: Daniel Bristot de Oliveira <bristot@kernel.org>
To: Tero Kristo <tero.kristo@linux.intel.com>,
rostedt@goodmis.org, mhiramat@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCHv2 2/2] trace/hwlat: Do not start per-cpu thread if it is already running
Date: Fri, 10 Mar 2023 14:52:34 +0100 [thread overview]
Message-ID: <21a188b3-d3f9-ac13-4e9b-d870401b074f@kernel.org> (raw)
In-Reply-To: <20230310100451.3948583-3-tero.kristo@linux.intel.com>
On 3/10/23 11:04, Tero Kristo wrote:
> The hwlatd tracer will end up starting multiple per-cpu threads with
> the following script:
>
> #!/bin/sh
> cd /sys/kernel/debug/tracing
> echo 0 > tracing_on
> echo hwlat > current_tracer
> echo per-cpu > hwlat_detector/mode
> echo 100000 > hwlat_detector/width
> echo 200000 > hwlat_detector/window
> echo 1 > tracing_on
>
> To fix the issue, check if the hwlatd thread for the cpu is already
> running, before starting a new one. Along with the previous patch, this
> avoids running multiple instances of the same CPU thread on the system.
>
> Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
-- Daniel
prev parent reply other threads:[~2023-03-10 13:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-10 10:04 [PATCHv2 0/2] trace/hwlat: Prevent startup of multiple per-cpu threads Tero Kristo
2023-03-10 10:04 ` [PATCHv2 1/2] trace/hwlat: Do not wipe the contents of per-cpu thread data Tero Kristo
2023-03-10 13:52 ` Daniel Bristot de Oliveira
2023-03-10 10:04 ` [PATCHv2 2/2] trace/hwlat: Do not start per-cpu thread if it is already running Tero Kristo
2023-03-10 13:52 ` Daniel Bristot de Oliveira [this message]
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