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Add taskq contention splat test

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Add a test designed to generate contention on the taskq spinlock by
using a large number of threads (100) to perform a large number (131072)
of trivial work items from a single queue.  This simulates conditions
that may occur with the zio free taskq when a 1TB file is removed from a
ZFS filesystem, for example.  This test should always pass.  Its purpose
is to provide a benchmark to easily measure the effectiveness of taskq
optimizations using statistics from the kernel lock profiler.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #32
This commit is contained in:
Ned Bass 2012-01-17 14:23:58 -08:00 committed by Brian Behlendorf
parent 966e5200d3
commit cf5d23fa1e
1 changed files with 115 additions and 0 deletions
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115
module/splat/splat-taskq.c
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@ -57,9 +57,14 @@
#define SPLAT_TASKQ_TEST7_NAME "recurse"
#define SPLAT_TASKQ_TEST7_DESC "Single task queue, recursive dispatch"
#define SPLAT_TASKQ_TEST8_ID 0x0208
#define SPLAT_TASKQ_TEST8_NAME "contention"
#define SPLAT_TASKQ_TEST8_DESC "1 queue, 100 threads, 131072 tasks"
#define SPLAT_TASKQ_ORDER_MAX 8
#define SPLAT_TASKQ_DEPTH_MAX 16
typedef struct splat_taskq_arg {
int flag;
int id;
@ -990,6 +995,113 @@ splat_taskq_test7(struct file *file, void *arg)
return rc;
}
/*
* Create a taskq with 100 threads and dispatch a huge number of trivial
* tasks to generate contention on tq->tq_lock. This test should always
* pass. The purpose is to provide a benchmark for measuring the
* effectiveness of taskq optimizations.
*/
static void
splat_taskq_test8_func(void *arg)
{
splat_taskq_arg_t *tq_arg = (splat_taskq_arg_t *)arg;
ASSERT(tq_arg);
atomic_inc(&tq_arg->count);
}
#define TEST8_NUM_TASKS 0x20000
#define TEST8_THREADS_PER_TASKQ 100
static int
splat_taskq_test8_common(struct file *file, void *arg, int minalloc,
int maxalloc)
{
taskq_t *tq;
taskqid_t id;
splat_taskq_arg_t tq_arg;
taskq_ent_t **tqes;
int i, j, rc = 0;
tqes = vmalloc(sizeof(*tqes) * TEST8_NUM_TASKS);
if (tqes == NULL)
return -ENOMEM;
memset(tqes, 0, sizeof(*tqes) * TEST8_NUM_TASKS);
splat_vprint(file, SPLAT_TASKQ_TEST8_NAME,
"Taskq '%s' creating (%d/%d/%d)\n",
SPLAT_TASKQ_TEST8_NAME,
minalloc, maxalloc, TEST8_NUM_TASKS);
if ((tq = taskq_create(SPLAT_TASKQ_TEST8_NAME, TEST8_THREADS_PER_TASKQ,
maxclsyspri, minalloc, maxalloc,
TASKQ_PREPOPULATE)) == NULL) {
splat_vprint(file, SPLAT_TASKQ_TEST8_NAME,
"Taskq '%s' create failed\n",
SPLAT_TASKQ_TEST8_NAME);
rc = -EINVAL;
goto out_free;
}
tq_arg.file = file;
tq_arg.name = SPLAT_TASKQ_TEST8_NAME;
atomic_set(&tq_arg.count, 0);
for (i = 0; i < TEST8_NUM_TASKS; i++) {
tqes[i] = kmalloc(sizeof(taskq_ent_t), GFP_KERNEL);
if (tqes[i] == NULL) {
rc = -ENOMEM;
goto out;
}
taskq_init_ent(tqes[i]);
taskq_dispatch_ent(tq, splat_taskq_test8_func,
&tq_arg, TQ_SLEEP, tqes[i]);
id = tqes[i]->tqent_id;
if (id == 0) {
splat_vprint(file, SPLAT_TASKQ_TEST8_NAME,
"Taskq '%s' function '%s' dispatch "
"%d failed\n", tq_arg.name,
sym2str(splat_taskq_test8_func), i);
rc = -EINVAL;
goto out;
}
}
splat_vprint(file, SPLAT_TASKQ_TEST8_NAME, "Taskq '%s' "
"waiting for %d dispatches\n", tq_arg.name,
TEST8_NUM_TASKS);
taskq_wait(tq);
splat_vprint(file, SPLAT_TASKQ_TEST8_NAME, "Taskq '%s' "
"%d/%d dispatches finished\n", tq_arg.name,
atomic_read(&tq_arg.count), TEST8_NUM_TASKS);
if (atomic_read(&tq_arg.count) != TEST8_NUM_TASKS)
rc = -ERANGE;
out:
splat_vprint(file, SPLAT_TASKQ_TEST8_NAME, "Taskq '%s' destroying\n",
tq_arg.name);
taskq_destroy(tq);
out_free:
for (j = 0; j < TEST8_NUM_TASKS && tqes[j] != NULL; j++)
kfree(tqes[j]);
vfree(tqes);
return rc;
}
static int
splat_taskq_test8(struct file *file, void *arg)
{
int rc;
rc = splat_taskq_test8_common(file, arg, 1, 100);
return rc;
}
splat_subsystem_t *
splat_taskq_init(void)
{
@ -1021,6 +1133,8 @@ splat_taskq_init(void)
SPLAT_TASKQ_TEST6_ID, splat_taskq_test6);
SPLAT_TEST_INIT(sub, SPLAT_TASKQ_TEST7_NAME, SPLAT_TASKQ_TEST7_DESC,
SPLAT_TASKQ_TEST7_ID, splat_taskq_test7);
SPLAT_TEST_INIT(sub, SPLAT_TASKQ_TEST8_NAME, SPLAT_TASKQ_TEST8_DESC,
SPLAT_TASKQ_TEST8_ID, splat_taskq_test8);
return sub;
}
@ -1029,6 +1143,7 @@ void
splat_taskq_fini(splat_subsystem_t *sub)
{
ASSERT(sub);
SPLAT_TEST_FINI(sub, SPLAT_TASKQ_TEST8_ID);
SPLAT_TEST_FINI(sub, SPLAT_TASKQ_TEST7_ID);
SPLAT_TEST_FINI(sub, SPLAT_TASKQ_TEST6_ID);
SPLAT_TEST_FINI(sub, SPLAT_TASKQ_TEST5_ID);