Add another kmem test to check for lock contention in the slab
allocator. I have serious contention issues here and I needed
a way to easily measure how much the following batch of changes
will improve things. Currently things are quite bad when the
allocator is highly contended, and interestingly it seems to
get worse in a non-linear fashion... I'm not sure why yet.
I'll figure it out tomorrow.
kmem:kmem_lock Pass
kmem_lock: time (sec) slabs objs
kmem_lock: tot/max/calc tot/max/calc
kmem_lock: 0.061000000 75/60/64 2400/1894/2048
kmem_lock: 0.157000000 134/125/128 4288/3974/4096
kmem_lock: 0.471000000 263/249/256 8416/7962/8192
kmem_lock: 2.526000000 518/499/512 16576/15957/16384
kmem_lock: 14.393000000 990/978/1024 31680/31270/32768
git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@134 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c
This commit is contained in:
behlendo
parent
5cbd57fa91
commit
44b8f1769f
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@ -58,9 +58,31 @@
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#define SPLAT_KMEM_TEST7_NAME "kmem_reap"
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#define SPLAT_KMEM_TEST7_DESC "Slab reaping test"
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#define SPLAT_KMEM_TEST8_ID 0x0108
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#define SPLAT_KMEM_TEST8_NAME "kmem_lock"
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#define SPLAT_KMEM_TEST8_DESC "Slab locking test"
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#define SPLAT_KMEM_ALLOC_COUNT 10
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#define SPLAT_VMEM_ALLOC_COUNT 10
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/* Not exported from the kernel, but we need it for timespec_sub. Be very
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* * careful here we are using the kernel prototype, so that must not change.
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* */
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void
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set_normalized_timespec(struct timespec *ts, time_t sec, long nsec)
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{
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while (nsec >= NSEC_PER_SEC) {
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nsec -= NSEC_PER_SEC;
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++sec;
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}
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while (nsec < 0) {
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nsec += NSEC_PER_SEC;
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--sec;
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}
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ts->tv_sec = sec;
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ts->tv_nsec = nsec;
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}
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/* XXX - This test may fail under tight memory conditions */
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static int
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splat_kmem_test1(struct file *file, void *arg)
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@ -242,8 +264,12 @@ typedef struct kmem_cache_priv {
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struct file *kcp_file;
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kmem_cache_t *kcp_cache;
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kmem_cache_data_t *kcp_kcd[SPLAT_KMEM_OBJ_COUNT];
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spinlock_t kcp_lock;
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wait_queue_head_t kcp_waitq;
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int kcp_size;
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int kcp_count;
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int kcp_threads;
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int kcp_alloc;
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int kcp_rc;
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} kmem_cache_priv_t;
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@ -488,6 +514,135 @@ splat_kmem_test7(struct file *file, void *arg)
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return rc;
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}
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static void
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splat_kmem_test8_thread(void *arg)
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{
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kmem_cache_priv_t *kcp = (kmem_cache_priv_t *)arg;
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int count = kcp->kcp_alloc, rc = 0, i;
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void **objs;
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ASSERT(kcp->kcp_magic == SPLAT_KMEM_TEST_MAGIC);
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objs = vmem_zalloc(count * sizeof(void *), KM_SLEEP);
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if (!objs) {
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rc = -ENOMEM;
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goto out;
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}
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for (i = 0; i < count; i++) {
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objs[i] = kmem_cache_alloc(kcp->kcp_cache, KM_SLEEP);
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if (!objs[i]) {
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splat_vprint(kcp->kcp_file, SPLAT_KMEM_TEST8_NAME,
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"Unable to allocate from '%s'\n",
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SPLAT_KMEM_CACHE_NAME);
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rc = -ENOMEM;
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goto out_free;
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}
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}
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out_free:
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for (i = 0; i < count; i++)
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if (objs[i])
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kmem_cache_free(kcp->kcp_cache, objs[i]);
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vmem_free(objs, count * sizeof(void *));
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out:
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spin_lock(&kcp->kcp_lock);
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kcp->kcp_threads--;
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if (!kcp->kcp_rc)
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kcp->kcp_rc = rc;
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spin_unlock(&kcp->kcp_lock);
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wake_up(&kcp->kcp_waitq);
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thread_exit();
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}
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static int
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splat_kmem_test8_count(kmem_cache_priv_t *kcp, int threads)
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{
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int ret;
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spin_lock(&kcp->kcp_lock);
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ret = (kcp->kcp_threads == threads);
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spin_unlock(&kcp->kcp_lock);
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return ret;
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}
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/* This test will always pass and is simply here so I can easily
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* eyeball the slab cache locking overhead to ensure it is reasonable.
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*/
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static int
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splat_kmem_test8(struct file *file, void *arg)
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{
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kmem_cache_priv_t kcp;
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kthread_t *thr;
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struct timespec start, stop, delta;
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int alloc, i;
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kcp.kcp_magic = SPLAT_KMEM_TEST_MAGIC;
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kcp.kcp_file = file;
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splat_vprint(file, SPLAT_KMEM_TEST8_NAME, "%s",
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"time (sec)\tslabs \tobjs\n");
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splat_vprint(file, SPLAT_KMEM_TEST8_NAME, "%s",
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" \ttot/max/calc\ttot/max/calc\n");
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for (alloc = 64; alloc <= 1024; alloc *= 2) {
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kcp.kcp_size = 256;
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kcp.kcp_count = 0;
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kcp.kcp_threads = 0;
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kcp.kcp_alloc = alloc;
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kcp.kcp_rc = 0;
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spin_lock_init(&kcp.kcp_lock);
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init_waitqueue_head(&kcp.kcp_waitq);
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kcp.kcp_cache = kmem_cache_create(SPLAT_KMEM_CACHE_NAME,
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kcp.kcp_size, 0,
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splat_kmem_cache_test_constructor,
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splat_kmem_cache_test_destructor,
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NULL, &kcp, NULL, 0);
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if (!kcp.kcp_cache) {
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splat_vprint(file, SPLAT_KMEM_TEST8_NAME,
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"Unable to create '%s' cache\n",
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SPLAT_KMEM_CACHE_NAME);
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return -ENOMEM;
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}
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start = current_kernel_time();
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for (i = 0; i < 32; i++) {
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thr = thread_create(NULL, 0, splat_kmem_test8_thread,
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&kcp, 0, &p0, TS_RUN, minclsyspri);
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ASSERT(thr != NULL);
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kcp.kcp_threads++;
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}
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/* Sleep until the thread sets kcp.kcp_threads == 0 */
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wait_event(kcp.kcp_waitq, splat_kmem_test8_count(&kcp, 0));
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stop = current_kernel_time();
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delta = timespec_sub(stop, start);
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splat_vprint(file, SPLAT_KMEM_TEST8_NAME, "%2ld.%09ld\t"
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"%lu/%lu/%lu\t%lu/%lu/%lu\n",
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delta.tv_sec, delta.tv_nsec,
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(unsigned long)kcp.kcp_cache->skc_slab_total,
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(unsigned long)kcp.kcp_cache->skc_slab_max,
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(unsigned long)(kcp.kcp_alloc * 32 / SPL_KMEM_CACHE_OBJ_PER_SLAB),
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(unsigned long)kcp.kcp_cache->skc_obj_total,
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(unsigned long)kcp.kcp_cache->skc_obj_max,
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(unsigned long)(kcp.kcp_alloc * 32));
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kmem_cache_destroy(kcp.kcp_cache);
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if (kcp.kcp_rc)
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break;
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}
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return kcp.kcp_rc;
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}
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splat_subsystem_t *
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splat_kmem_init(void)
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{
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SPLAT_KMEM_TEST6_ID, splat_kmem_test6);
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SPLAT_TEST_INIT(sub, SPLAT_KMEM_TEST7_NAME, SPLAT_KMEM_TEST7_DESC,
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SPLAT_KMEM_TEST7_ID, splat_kmem_test7);
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SPLAT_TEST_INIT(sub, SPLAT_KMEM_TEST8_NAME, SPLAT_KMEM_TEST8_DESC,
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SPLAT_KMEM_TEST8_ID, splat_kmem_test8);
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return sub;
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}
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@ -527,6 +684,7 @@ void
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splat_kmem_fini(splat_subsystem_t *sub)
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{
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ASSERT(sub);
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SPLAT_TEST_FINI(sub, SPLAT_KMEM_TEST8_ID);
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SPLAT_TEST_FINI(sub, SPLAT_KMEM_TEST7_ID);
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SPLAT_TEST_FINI(sub, SPLAT_KMEM_TEST6_ID);
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SPLAT_TEST_FINI(sub, SPLAT_KMEM_TEST5_ID);
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