From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Mike Leach <mike.leach@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org,
suzuki.poulose@arm.com, leo.yan@linaro.org
Subject: Re: [PATCH v3 6/6] Documentation: coresight: Update coresight configuration docs
Date: Fri, 26 Nov 2021 11:26:22 -0700 [thread overview]
Message-ID: <20211126182622.GB167936@p14s> (raw)
In-Reply-To: <20211124200038.28662-7-mike.leach@linaro.org>
On Wed, Nov 24, 2021 at 08:00:38PM +0000, Mike Leach wrote:
> Update the CoreSight System Configuration document to cover the
> use of loadable modules to add configurations and features
> to the system.
>
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> ---
> .../trace/coresight/coresight-config.rst | 62 ++++++++++++++++++-
> 1 file changed, 59 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documentation/trace/coresight/coresight-config.rst
> index 6ed13398ca2c..6d5ffa6f7347 100644
> --- a/Documentation/trace/coresight/coresight-config.rst
> +++ b/Documentation/trace/coresight/coresight-config.rst
> @@ -155,14 +155,14 @@ follows::
> autofdo
> $ cd autofdo/
> $ ls
> - description preset1 preset3 preset5 preset7 preset9
> - feature_refs preset2 preset4 preset6 preset8
> + description feature_refs preset1 preset3 preset5 preset7 preset9
> + enable preset preset2 preset4 preset6 preset8
> $ cat description
> Setup ETMs with strobing for autofdo
> $ cat feature_refs
> strobing
>
> -Each preset declared has a preset<n> subdirectory declared. The values for
> +Each preset declared has a 'preset<n>' subdirectory declared. The values for
> the preset can be examined::
>
> $ cat preset1/values
> @@ -170,6 +170,9 @@ the preset can be examined::
> $ cat preset2/values
> strobing.window = 0x1388 strobing.period = 0x4
>
> +The 'enable' and 'preset' files allow the control of a configuration when
> +using CoreSight with sysfs.
> +
> The features referenced by the configuration can be examined in the features
> directory::
>
> @@ -236,3 +239,56 @@ A preset to override the current parameter values can also be selected::
>
> When configurations are selected in this way, then the trace sink used is
> automatically selected.
> +
> +Using Configurations in sysfs
> +=============================
> +
> +Coresight can be controlled using sysfs. When this is in use then a configuration
> +can be made active for the devices that are used in the sysfs session.
> +
> +In a configuration there are 'enable' and 'preset' files.
> +
> +To enable a configuration for use with sysfs::
> +
> + $ cd configurations/autofdo
> + $ echo 1 > enable
> +
> +This will then use any default parameter values in the features - which can be
> +adjusted as described above.
> +
> +To use a preset<n> set of parameter values::
> +
> + $ echo 3 > preset
> +
> +This will select preset3 for the configuration.
> +The valid values for preset are 0 - to deselect presets, and any value of
> +<n> where a preset<n> sub-directory is present.
> +
> +Note that the active sysfs configuration is a global parameter, therefore
> +only a single configuration can be active for sysfs at any one time.
> +Attempting to enable a second configuration will result in an error.
> +Additionally, attempting to disable the configuration while in use will
> +also result in an error.
> +
> +The use of the active configuration by sysfs is independent of the configuration
> +used in perf.
> +
Shouldn't all instances in the above section be configfs rather than sysfs? If
so should I make the changes?
I have your patchset on stanby in my local coresight-next tree - just let me
know.
Thanks,
Mathieu
> +
> +Creating and Loading Custom Configurations
> +==========================================
> +
> +Custom configurations and / or features can be dynamically loaded into the
> +system by using a loadable module.
> +
> +An example of a custom configuration is found in ./samples/coresight.
> +
> +This creates a new configuration that uses the existing built in
> +strobing feature, but provides a different set of presets.
> +
> +When the module is loaded, then the configuration appears in the configfs
> +file system and is selectable in the same way as the built in configuration
> +described above.
> +
> +Configurations can use previously loaded features. The system will ensure
> +that it is not possible to unload a feature that is currently in use, by
> +enforcing the unload order as the strict reverse of the load order.
> --
> 2.17.1
>
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next prev parent reply other threads:[~2021-11-26 18:27 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 20:00 [PATCH v3 0/6] coresight: syscfg: dynamic load Mike Leach
2021-11-24 20:00 ` [PATCH v3 1/6] coresight: configuration: Update API to introduce load owner concept Mike Leach
2021-11-24 20:00 ` [PATCH v3 2/6] coresight: configuration: Update API to permit dynamic load/unload Mike Leach
2021-11-24 20:00 ` [PATCH v3 3/6] coresight: syscfg: Update load API for config loadable modules Mike Leach
2021-11-24 20:00 ` [PATCH v3 4/6] coresight: syscfg: Example CoreSight configuration loadable module Mike Leach
2021-11-26 18:23 ` Mathieu Poirier
2021-11-29 12:24 ` Mike Leach
2021-11-29 16:44 ` Mathieu Poirier
2021-11-24 20:00 ` [PATCH v3 5/6] coresight: configfs: Allow configfs to activate configuration Mike Leach
2021-11-24 20:00 ` [PATCH v3 6/6] Documentation: coresight: Update coresight configuration docs Mike Leach
2021-11-26 18:26 ` Mathieu Poirier [this message]
2021-11-29 11:54 ` Mike Leach
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