From: SeongJae Park <sj@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: SeongJae Park <sj@kernel.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
David Hildenbrand <david@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Michal Hocko <mhocko@suse.com>, Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
damon@lists.linux.dev, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH 7/8] Docs/admin-guide/mm/damon/stat: document aggr_interval_us parameter
Date: Sun, 26 Oct 2025 11:22:12 -0700 [thread overview]
Message-ID: <20251026182216.118200-8-sj@kernel.org> (raw)
In-Reply-To: <20251026182216.118200-1-sj@kernel.org>
Commit cc7ceb1d14b0 ("mm/damon/stat: expose the current tuned
aggregation interval"), has introduced 'aggr_interval_us' parameter for
DAMON_STAT. But the new parameter is not yet documented. Document it
on the usage document for the module.
Signed-off-by: SeongJae Park <sj@kernel.org>
---
Documentation/admin-guide/mm/damon/stat.rst | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/mm/damon/stat.rst b/Documentation/admin-guide/mm/damon/stat.rst
index 20f540a9d3d2..754f98d47617 100644
--- a/Documentation/admin-guide/mm/damon/stat.rst
+++ b/Documentation/admin-guide/mm/damon/stat.rst
@@ -10,6 +10,8 @@ on the system's entire physical memory using DAMON, and provides simplified
access monitoring results statistics, namely idle time percentiles and
estimated memory bandwidth.
+.. _damon_stat_monitoring_accuracy_overhead:
+
Monitoring Accuracy and Overhead
================================
@@ -19,7 +21,9 @@ overhead minimum. It auto-tunes the intervals aiming 4 % of observable access
events to be captured in each snapshot, while limiting the resulting sampling
interval to be 5 milliseconds in minimum and 10 seconds in maximum. On a few
production server systems, it resulted in consuming only 0.x % single CPU time,
-while capturing reasonable quality of access patterns.
+while capturing reasonable quality of access patterns. The tuning-resulting
+intervals can be retrieved via ``aggr_interval_us`` :ref:`parameter
+<damon_stat_aggr_interval_us>`.
Interface: Module Parameters
============================
@@ -41,6 +45,18 @@ You can enable DAMON_STAT by setting the value of this parameter as ``Y``.
Setting it as ``N`` disables DAMON_STAT. The default value is set by
``CONFIG_DAMON_STAT_ENABLED_DEFAULT`` build config option.
+.. _damon_stat_aggr_interval_us:
+
+aggr_interval_us
+----------------
+
+Auto-tuned aggregation time interval in microseconds.
+
+Users can read the aggregation interval of DAMON that is being used by the
+DAMON instance for DAMON_STAT. It is :ref:`auto-tuned
+<damon_stat_monitoring_accuracy_overhead>` and therefore the value is
+dynamically changed.
+
estimated_memory_bandwidth
--------------------------
--
2.47.3
next prev parent reply other threads:[~2025-10-26 18:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-26 18:22 [PATCH 0/8] mm/damon: misc documentation fixups SeongJae Park
2025-10-26 18:22 ` [PATCH 1/8] mm/damon/core: fix wrong comment of damon_call() return timing SeongJae Park
2025-10-26 18:22 ` [PATCH 2/8] Docs/mm/damon/design: fix wrong link to intervals goal section SeongJae Park
2025-10-26 18:22 ` [PATCH 3/8] Docs/admin-guide/mm/damon/stat: fix a typo: s/sampling events/sampling interval/ SeongJae Park
2025-10-26 18:22 ` [PATCH 4/8] Docs/admin-guide/mm/damon/usage: document empty target regions commit behavior SeongJae Park
2025-10-26 18:22 ` [PATCH 5/8] Docs/admin-guide/mm/damon/reclaim: document addr_unit parameter SeongJae Park
2025-10-26 18:22 ` [PATCH 6/8] Docs/admin-guide/mm/damon/lru_sort: " SeongJae Park
2025-10-26 18:22 ` SeongJae Park [this message]
2025-10-26 18:22 ` [PATCH 8/8] Docs/admin-guide/mm/damon/stat: document negative idle time SeongJae Park
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