Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 127 insertions, 0 deletions

diff --git a/Documentation/admin-guide/mm/damon/start.rst b/Documentation/admin-guide/mm/damon/start.rst
new file mode 100644
index 0000000000..7aa0071ff1
--- /dev/null
+++ b/Documentation/admin-guide/mm/damon/start.rst
@@ -0,0 +1,127 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===============
+Getting Started
+===============
+
+This document briefly describes how you can use DAMON by demonstrating its
+default user space tool.  Please note that this document describes only a part
+of its features for brevity.  Please refer to the usage `doc
+<https://github.com/awslabs/damo/blob/next/USAGE.md>`_ of the tool for more
+details.
+
+
+Prerequisites
+=============
+
+Kernel
+------
+
+You should first ensure your system is running on a kernel built with
+``CONFIG_DAMON_*=y``.
+
+
+User Space Tool
+---------------
+
+For the demonstration, we will use the default user space tool for DAMON,
+called DAMON Operator (DAMO).  It is available at
+https://github.com/awslabs/damo.  The examples below assume that ``damo`` is on
+your ``$PATH``.  It's not mandatory, though.
+
+Because DAMO is using the sysfs interface (refer to :doc:`usage` for the
+detail) of DAMON, you should ensure :doc:`sysfs </filesystems/sysfs>` is
+mounted.
+
+
+Recording Data Access Patterns
+==============================
+
+The commands below record the memory access patterns of a program and save the
+monitoring results to a file. ::
+
+    $ git clone https://github.com/sjp38/masim
+    $ cd masim; make; ./masim ./configs/zigzag.cfg &
+    $ sudo damo record -o damon.data $(pidof masim)
+
+The first two lines of the commands download an artificial memory access
+generator program and run it in the background.  The generator will repeatedly
+access two 100 MiB sized memory regions one by one.  You can substitute this
+with your real workload.  The last line asks ``damo`` to record the access
+pattern in the ``damon.data`` file.
+
+
+Visualizing Recorded Patterns
+=============================
+
+You can visualize the pattern in a heatmap, showing which memory region
+(x-axis) got accessed when (y-axis) and how frequently (number).::
+
+    $ sudo damo report heats --heatmap stdout
+    22222222222222222222222222222222222222211111111111111111111111111111111111111100
+    44444444444444444444444444444444444444434444444444444444444444444444444444443200
+    44444444444444444444444444444444444444433444444444444444444444444444444444444200
+    33333333333333333333333333333333333333344555555555555555555555555555555555555200
+    33333333333333333333333333333333333344444444444444444444444444444444444444444200
+    22222222222222222222222222222222222223355555555555555555555555555555555555555200
+    00000000000000000000000000000000000000288888888888888888888888888888888888888400
+    00000000000000000000000000000000000000288888888888888888888888888888888888888400
+    33333333333333333333333333333333333333355555555555555555555555555555555555555200
+    88888888888888888888888888888888888888600000000000000000000000000000000000000000
+    88888888888888888888888888888888888888600000000000000000000000000000000000000000
+    33333333333333333333333333333333333333444444444444444444444444444444444444443200
+    00000000000000000000000000000000000000288888888888888888888888888888888888888400
+    [...]
+    # access_frequency:  0  1  2  3  4  5  6  7  8  9
+    # x-axis: space (139728247021568-139728453431248: 196.848 MiB)
+    # y-axis: time (15256597248362-15326899978162: 1 m 10.303 s)
+    # resolution: 80x40 (2.461 MiB and 1.758 s for each character)
+
+You can also visualize the distribution of the working set size, sorted by the
+size.::
+
+    $ sudo damo report wss --range 0 101 10
+    # <percentile> <wss>
+    # target_id     18446632103789443072
+    # avr:  107.708 MiB
+      0             0 B |                                                           |
+     10      95.328 MiB |****************************                               |
+     20      95.332 MiB |****************************                               |
+     30      95.340 MiB |****************************                               |
+     40      95.387 MiB |****************************                               |
+     50      95.387 MiB |****************************                               |
+     60      95.398 MiB |****************************                               |
+     70      95.398 MiB |****************************                               |
+     80      95.504 MiB |****************************                               |
+     90     190.703 MiB |*********************************************************  |
+    100     196.875 MiB |***********************************************************|
+
+Using ``--sortby`` option with the above command, you can show how the working
+set size has chronologically changed.::
+
+    $ sudo damo report wss --range 0 101 10 --sortby time
+    # <percentile> <wss>
+    # target_id     18446632103789443072
+    # avr:  107.708 MiB
+      0       3.051 MiB |                                                           |
+     10     190.703 MiB |***********************************************************|
+     20      95.336 MiB |*****************************                              |
+     30      95.328 MiB |*****************************                              |
+     40      95.387 MiB |*****************************                              |
+     50      95.332 MiB |*****************************                              |
+     60      95.320 MiB |*****************************                              |
+     70      95.398 MiB |*****************************                              |
+     80      95.398 MiB |*****************************                              |
+     90      95.340 MiB |*****************************                              |
+    100      95.398 MiB |*****************************                              |
+
+
+Data Access Pattern Aware Memory Management
+===========================================
+
+Below command makes every memory region of size >=4K that has not accessed for
+>=60 seconds in your workload to be swapped out. ::
+
+    $ sudo damo schemes --damos_access_rate 0 0 --damos_sz_region 4K max \
+                        --damos_age 60s max --damos_action pageout \
+                        <pid of your workload>