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Evenly distribute the taskq threads across available CPUs 

The problem is described in commit aeeb4e0c0a.
However, instead of disabling the binding to CPU altogether we just keep the
last CPU index across calls to taskq_create() and thus achieve even
distribution of the taskq threads across all available CPUs.

The implementation based on assumption that task queues initialization
performed in serial manner.

Signed-off-by: Andrey Vesnovaty <andrey.vesnovaty@gmail.com>
Signed-off-by: Andrey Vesnovaty <andreyv@infinidat.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #336
This commit is contained in:
Andrey Vesnovaty 2013-08-28 05:09:25 +03:00 committed by Brian Behlendorf
parent ae16ed992b
commit 703371d8c7
2 changed files with 21 additions and 0 deletions
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12
man/man5/spl-module-parameters.5
View File

@ -124,3 +124,15 @@ Spin a maximum of N times to acquire lock
.sp
.ne -4
Default value: \fB0\fR.
.RE
.sp
.ne 2
.na
\fBspl_taskq_thread_bind\fR (int)
.ad
.RS 12n
Bind taskq thread to CPU
.sp
Default value: \fB0\fR.
.RE

9
module/spl/spl-taskq.c
View File

@ -34,6 +34,10 @@
#define SS_DEBUG_SUBSYS SS_TASKQ
int spl_taskq_thread_bind = 0;
module_param(spl_taskq_thread_bind, int, 0644);
MODULE_PARM_DESC(spl_taskq_thread_bind, "Bind taskq thread to CPU by default");
/* Global system-wide dynamic task queue available for all consumers */
taskq_t *system_taskq;
EXPORT_SYMBOL(system_taskq);
@ -781,6 +785,7 @@ taskq_t *
taskq_create(const char *name, int nthreads, pri_t pri,
int minalloc, int maxalloc, uint_t flags)
{
static int last_used_cpu = 0;
taskq_t *tq;
taskq_thread_t *tqt;
int rc = 0, i, j = 0;
@ -843,6 +848,10 @@ taskq_create(const char *name, int nthreads, pri_t pri,
"%s/%d", name, i);
if (tqt->tqt_thread) {
list_add(&tqt->tqt_thread_list, &tq->tq_thread_list);
if (spl_taskq_thread_bind) {
last_used_cpu = (last_used_cpu + 1) % num_online_cpus();
kthread_bind(tqt->tqt_thread, last_used_cpu);
}
set_user_nice(tqt->tqt_thread, PRIO_TO_NICE(pri));
wake_up_process(tqt->tqt_thread);
j++;