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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:36 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:36 +0000 |
commit | 50ba0232fd5312410f1b65247e774244f89a628e (patch) | |
tree | fd8f2fc78e9e548af0ff9590276602ee6125be00 /Documentation/admin-guide/kernel-per-CPU-kthreads.rst | |
parent | Releasing progress-linux version 6.7.12-1~progress7.99u1. (diff) | |
download | linux-50ba0232fd5312410f1b65247e774244f89a628e.tar.xz linux-50ba0232fd5312410f1b65247e774244f89a628e.zip |
Merging upstream version 6.8.9.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/admin-guide/kernel-per-CPU-kthreads.rst')
-rw-r--r-- | Documentation/admin-guide/kernel-per-CPU-kthreads.rst | 16 |
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 993c2a05f5..b6aeae3327 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(). |