Commit 64f26e5c authored by Paul E. McKenney's avatar Paul E. McKenney

kthread: Add pointer to vmstat-avoidance patch

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent 64d3b7a1
......@@ -181,12 +181,17 @@ 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().
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.
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.
......
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