linux_dsm_epyc7002/Documentation/ABI/testing/sysfs-bus-intel_th-devices-msc
Alexander Shishkin 6cac7866c2 intel_th: msu: Add a sysfs attribute to trigger window switch
Now that we have the means to trigger a window switch for the MSU trace
store, add a sysfs file to allow triggering it from userspace.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-03 18:17:40 +02:00

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What: /sys/bus/intel_th/devices/<intel_th_id>-msc<msc-id>/wrap
Date: June 2015
KernelVersion: 4.3
Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Description: (RW) Configure MSC buffer wrapping. 1 == wrapping enabled.
What: /sys/bus/intel_th/devices/<intel_th_id>-msc<msc-id>/mode
Date: June 2015
KernelVersion: 4.3
Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Description: (RW) Configure MSC operating mode:
- "single", for contiguous buffer mode (high-order alloc);
- "multi", for multiblock mode;
- "ExI", for DCI handler mode;
- "debug", for debug mode.
If operating mode changes, existing buffer is deallocated,
provided there are no active users and tracing is not enabled,
otherwise the write will fail.
What: /sys/bus/intel_th/devices/<intel_th_id>-msc<msc-id>/nr_pages
Date: June 2015
KernelVersion: 4.3
Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Description: (RW) Configure MSC buffer size for "single" or "multi" modes.
In single mode, this is a single number of pages, has to be
power of 2. In multiblock mode, this is a comma-separated list
of numbers of pages for each window to be allocated. Number of
windows is not limited.
Writing to this file deallocates existing buffer (provided
there are no active users and tracing is not enabled) and then
allocates a new one.
What: /sys/bus/intel_th/devices/<intel_th_id>-msc<msc-id>/win_switch
Date: May 2019
KernelVersion: 5.2
Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Description: (RW) Trigger window switch for the MSC's buffer, in
multi-window mode. In "multi" mode, accepts writes of "1", thereby
triggering a window switch for the buffer. Returns an error in any
other operating mode or attempts to write something other than "1".