summaryrefslogtreecommitdiff
path: root/Documentation/admin-guide/kernel-per-CPU-kthreads.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/admin-guide/kernel-per-CPU-kthreads.rst')
-rw-r--r--Documentation/admin-guide/kernel-per-CPU-kthreads.rst16
1 files changed, 6 insertions, 10 deletions
diff --git a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst
index 993c2a05f5ee..b6aeae3327ce 100644
--- a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst
+++ b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst
@@ -243,13 +243,9 @@ To reduce its OS jitter, do any of the following:
3. Do any of the following needed to avoid jitter that your
application cannot tolerate:
- a. Build your kernel with CONFIG_SLUB=y rather than
- CONFIG_SLAB=y, thus avoiding the slab allocator's periodic
- use of each CPU's workqueues to run its cache_reap()
- function.
- b. Avoid using oprofile, thus avoiding OS jitter from
+ a. Avoid using oprofile, thus avoiding OS jitter from
wq_sync_buffer().
- c. Limit your CPU frequency so that a CPU-frequency
+ b. Limit your CPU frequency so that a CPU-frequency
governor is not required, possibly enlisting the aid of
special heatsinks or other cooling technologies. If done
correctly, and if you CPU architecture permits, you should
@@ -259,7 +255,7 @@ To reduce its OS jitter, do any of the following:
WARNING: Please check your CPU specifications to
make sure that this is safe on your particular system.
- d. As of v3.18, Christoph Lameter's on-demand vmstat workers
+ c. As of v3.18, Christoph Lameter's on-demand vmstat workers
commit prevents OS jitter due to vmstat_update() on
CONFIG_SMP=y systems. Before v3.18, is not possible
to entirely get rid of the OS jitter, but you can
@@ -274,7 +270,7 @@ To reduce its OS jitter, do any of the following:
(based on an earlier one from Gilad Ben-Yossef) that
reduces or even eliminates vmstat overhead for some
workloads at https://lore.kernel.org/r/00000140e9dfd6bd-40db3d4f-c1be-434f-8132-7820f81bb586-000000@email.amazonses.com.
- e. If running on high-end powerpc servers, build with
+ d. If running on high-end powerpc servers, build with
CONFIG_PPC_RTAS_DAEMON=n. This prevents the RTAS
daemon from running on each CPU every second or so.
(This will require editing Kconfig files and will defeat
@@ -282,12 +278,12 @@ To reduce its OS jitter, do any of the following:
due to the rtas_event_scan() function.
WARNING: Please check your CPU specifications to
make sure that this is safe on your particular system.
- f. If running on Cell Processor, build your kernel with
+ e. If running on Cell Processor, build your kernel with
CBE_CPUFREQ_SPU_GOVERNOR=n to avoid OS jitter from
spu_gov_work().
WARNING: Please check your CPU specifications to
make sure that this is safe on your particular system.
- g. If running on PowerMAC, build your kernel with
+ f. If running on PowerMAC, build your kernel with
CONFIG_PMAC_RACKMETER=n to disable the CPU-meter,
avoiding OS jitter from rackmeter_do_timer().