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Diffstat (limited to 'Documentation/kernel-per-CPU-kthreads.txt')
| -rw-r--r-- | Documentation/kernel-per-CPU-kthreads.txt | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/Documentation/kernel-per-CPU-kthreads.txt b/Documentation/kernel-per-CPU-kthreads.txt index 827104f..32351bf 100644 --- a/Documentation/kernel-per-CPU-kthreads.txt +++ b/Documentation/kernel-per-CPU-kthreads.txt @@ -181,17 +181,12 @@ To reduce its OS jitter, do any of the following: make sure that this is safe on your particular system. d. It is not possible to entirely get rid of OS jitter from vmstat_update() on CONFIG_SMP=y systems, but you - can decrease its frequency by writing a large value - to /proc/sys/vm/stat_interval. The default value is - HZ, for an interval of one second. Of course, larger - values will make your virtual-memory statistics update - more slowly. Of course, you can also run your workload - at a real-time priority, thus preempting vmstat_update(), - but if your workload is CPU-bound, this is a bad idea. - However, there is an RFC patch from Christoph Lameter - (based on an earlier one from Gilad Ben-Yossef) that - reduces or even eliminates vmstat overhead for some - workloads at https://lkml.org/lkml/2013/9/4/379. + can decrease its frequency by writing a large value to + /proc/sys/vm/stat_interval. The default value is HZ, + for an interval of one second. Of course, larger values + will make your virtual-memory statistics update more + slowly. Of course, you can also run your workload at + a real-time priority, thus preempting vmstat_update(). e. 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. |