Add two new kernel options to allow rudimentary profiling of the internal
hash tables used in the sleep queue and turnstile code. Each option adds a sysctl tree under debug containing the maximum depth of any bucket in the hash table as well as a separate node for each bucket (or chain) containing the current depth and maximum depth for that bucket.
This commit is contained in:
John Baldwin
parent
c796e27ba8
commit
ef0ebfc351
@ -181,6 +181,10 @@ options MUTEX_NOINLINE
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# SMP Debugging Options:
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#
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# MUTEX_DEBUG enables various extra assertions in the mutex code.
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# SLEEPQUEUE_PROFILING enables rudimentary profiling of the hash table
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# used to hold active sleep queues.
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# TURNSTILE_PROFILING enables rudimentary profiling of the hash table
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# used to hold active lock queues.
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# WITNESS enables the witness code which detects deadlocks and cycles
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# during locking operations.
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# WITNESS_DDB causes the witness code to drop into the kernel debugger if
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@ -196,6 +200,10 @@ options WITNESS_SKIPSPIN
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# MUTEX_PROFILING(9) for details.
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options MUTEX_PROFILING
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# Profiling for internal hash tables.
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options SLEEPQUEUE_PROFILING
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options TURNSTILE_PROFILING
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#####################################################################
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# COMPATIBILITY OPTIONS
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@ -110,6 +110,7 @@ QUOTA
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SCHED_4BSD opt_sched.h
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SCHED_ULE opt_sched.h
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SHOW_BUSYBUFS
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SLEEPQUEUE_PROFILING
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SPX_HACK
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SUIDDIR opt_suiddir.h
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MSGMNB opt_sysvipc.h
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@ -134,6 +135,7 @@ SYSVMSG opt_sysvipc.h
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SYSVSEM opt_sysvipc.h
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SYSVSHM opt_sysvipc.h
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SW_WATCHDOG opt_watchdog.h
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TURNSTILE_PROFILING
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TTYHOG opt_tty.h
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VFS_AIO
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WLCACHE opt_wavelan.h
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@ -59,6 +59,8 @@
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* variables.
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*/
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#include "opt_sleepqueue_profiling.h"
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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@ -73,6 +75,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/sched.h>
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#include <sys/signalvar.h>
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#include <sys/sleepqueue.h>
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#include <sys/sysctl.h>
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/*
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* Constants for the hash table of sleep queue chains. These constants are
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@ -119,8 +122,20 @@ struct sleepqueue {
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struct sleepqueue_chain {
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LIST_HEAD(, sleepqueue) sc_queues; /* List of sleep queues. */
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struct mtx sc_lock; /* Spin lock for this chain. */
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#ifdef SLEEPQUEUE_PROFILING
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u_int sc_depth; /* Length of sc_queues. */
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u_int sc_max_depth; /* Max length of sc_queues. */
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#endif
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};
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#ifdef SLEEPQUEUE_PROFILING
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u_int sleepq_max_depth;
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SYSCTL_NODE(_debug, OID_AUTO, sleepq, CTLFLAG_RD, 0, "sleepq profiling");
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SYSCTL_NODE(_debug_sleepq, OID_AUTO, chains, CTLFLAG_RD, 0,
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"sleepq chain stats");
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SYSCTL_UINT(_debug_sleepq, OID_AUTO, max_depth, CTLFLAG_RD, &sleepq_max_depth,
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0, "maxmimum depth achieved of a single chain");
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#endif
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static struct sleepqueue_chain sleepq_chains[SC_TABLESIZE];
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MALLOC_DEFINE(M_SLEEPQUEUE, "sleep queues", "sleep queues");
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@ -141,12 +156,27 @@ static void sleepq_resume_thread(struct thread *td, int pri);
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void
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init_sleepqueues(void)
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{
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#ifdef SLEEPQUEUE_PROFILING
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struct sysctl_oid *chain_oid;
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char chain_name[10];
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#endif
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int i;
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for (i = 0; i < SC_TABLESIZE; i++) {
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LIST_INIT(&sleepq_chains[i].sc_queues);
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mtx_init(&sleepq_chains[i].sc_lock, "sleepq chain", NULL,
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MTX_SPIN);
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#ifdef SLEEPQUEUE_PROFILING
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snprintf(chain_name, sizeof(chain_name), "%d", i);
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chain_oid = SYSCTL_ADD_NODE(NULL,
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SYSCTL_STATIC_CHILDREN(_debug_sleepq_chains), OID_AUTO,
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chain_name, CTLFLAG_RD, NULL, "sleepq chain stats");
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SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
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"depth", CTLFLAG_RD, &sleepq_chains[i].sc_depth, 0, NULL);
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SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
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"max_depth", CTLFLAG_RD, &sleepq_chains[i].sc_max_depth, 0,
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NULL);
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#endif
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}
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thread0.td_sleepqueue = sleepq_alloc();
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}
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@ -230,6 +260,14 @@ sleepq_add(struct sleepqueue *sq, void *wchan, struct mtx *lock,
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/* If the passed in sleep queue is NULL, use this thread's queue. */
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if (sq == NULL) {
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#ifdef SLEEPQUEUE_PROFILING
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sc->sc_depth++;
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if (sc->sc_depth > sc->sc_max_depth) {
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sc->sc_max_depth = sc->sc_depth;
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if (sc->sc_max_depth > sleepq_max_depth)
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sleepq_max_depth = sc->sc_max_depth;
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}
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#endif
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sq = td->td_sleepqueue;
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LIST_INSERT_HEAD(&sc->sc_queues, sq, sq_hash);
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KASSERT(TAILQ_EMPTY(&sq->sq_blocked),
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@ -554,6 +592,9 @@ sleepq_remove_thread(struct sleepqueue *sq, struct thread *td)
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td->td_sleepqueue = sq;
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#ifdef INVARIANTS
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sq->sq_wchan = NULL;
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#endif
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#ifdef SLEEPQUEUE_PROFILING
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sc->sc_depth--;
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#endif
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} else
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td->td_sleepqueue = LIST_FIRST(&sq->sq_free);
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@ -56,6 +56,8 @@
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* it from the hash table.
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*/
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#include "opt_turnstile_profiling.h"
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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@ -69,8 +71,9 @@ __FBSDID("$FreeBSD$");
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#include <sys/proc.h>
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#include <sys/queue.h>
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#include <sys/resourcevar.h>
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#include <sys/turnstile.h>
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#include <sys/sched.h>
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#include <sys/sysctl.h>
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#include <sys/turnstile.h>
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/*
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* Constants for the hash table of turnstile chains. TC_SHIFT is a magic
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@ -116,8 +119,20 @@ struct turnstile {
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struct turnstile_chain {
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LIST_HEAD(, turnstile) tc_turnstiles; /* List of turnstiles. */
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struct mtx tc_lock; /* Spin lock for this chain. */
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#ifdef TURNSTILE_PROFILING
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u_int tc_depth; /* Length of tc_queues. */
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u_int tc_max_depth; /* Max length of tc_queues. */
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#endif
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};
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#ifdef TURNSTILE_PROFILING
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u_int turnstile_max_depth;
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SYSCTL_NODE(_debug, OID_AUTO, turnstile, CTLFLAG_RD, 0, "turnstile profiling");
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SYSCTL_NODE(_debug_turnstile, OID_AUTO, chains, CTLFLAG_RD, 0,
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"turnstile chain stats");
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SYSCTL_UINT(_debug_turnstile, OID_AUTO, max_depth, CTLFLAG_RD,
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&turnstile_max_depth, 0, "maxmimum depth achieved of a single chain");
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#endif
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static struct mtx td_contested_lock;
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static struct turnstile_chain turnstile_chains[TC_TABLESIZE];
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@ -292,12 +307,28 @@ propagate_priority(struct thread *td)
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void
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init_turnstiles(void)
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{
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#ifdef TURNSTILE_PROFILING
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struct sysctl_oid *chain_oid;
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char chain_name[10];
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#endif
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int i;
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for (i = 0; i < TC_TABLESIZE; i++) {
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LIST_INIT(&turnstile_chains[i].tc_turnstiles);
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mtx_init(&turnstile_chains[i].tc_lock, "turnstile chain",
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NULL, MTX_SPIN);
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#ifdef TURNSTILE_PROFILING
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snprintf(chain_name, sizeof(chain_name), "%d", i);
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chain_oid = SYSCTL_ADD_NODE(NULL,
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SYSCTL_STATIC_CHILDREN(_debug_turnstile_chains), OID_AUTO,
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chain_name, CTLFLAG_RD, NULL, "turnstile chain stats");
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SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
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"depth", CTLFLAG_RD, &turnstile_chains[i].tc_depth, 0,
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NULL);
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SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
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"max_depth", CTLFLAG_RD, &turnstile_chains[i].tc_max_depth,
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0, NULL);
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#endif
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}
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mtx_init(&td_contested_lock, "td_contested", NULL, MTX_SPIN);
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thread0.td_turnstile = NULL;
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@ -438,6 +469,14 @@ turnstile_wait(struct turnstile *ts, struct lock_object *lock,
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/* If the passed in turnstile is NULL, use this thread's turnstile. */
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if (ts == NULL) {
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#ifdef TURNSTILE_PROFILING
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tc->tc_depth++;
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if (tc->tc_depth > tc->tc_max_depth) {
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tc->tc_max_depth = tc->tc_depth;
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if (tc->tc_max_depth > turnstile_max_depth)
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turnstile_max_depth = tc->tc_max_depth;
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}
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#endif
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ts = td->td_turnstile;
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LIST_INSERT_HEAD(&tc->tc_turnstiles, ts, ts_hash);
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KASSERT(TAILQ_EMPTY(&ts->ts_pending),
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@ -551,9 +590,12 @@ turnstile_signal(struct turnstile *ts)
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* turnstile from the free list and give it to the thread.
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*/
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empty = TAILQ_EMPTY(&ts->ts_blocked);
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if (empty)
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if (empty) {
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MPASS(LIST_EMPTY(&ts->ts_free));
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else
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#ifdef TURNSTILE_PROFILING
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tc->tc_depth--;
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#endif
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} else
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ts = LIST_FIRST(&ts->ts_free);
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MPASS(ts != NULL);
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LIST_REMOVE(ts, ts_hash);
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@ -594,6 +636,9 @@ turnstile_broadcast(struct turnstile *ts)
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if (LIST_EMPTY(&ts->ts_free)) {
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MPASS(TAILQ_NEXT(td, td_lockq) == NULL);
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ts1 = ts;
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#ifdef TURNSTILE_PROFILING
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tc->tc_depth--;
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#endif
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} else
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ts1 = LIST_FIRST(&ts->ts_free);
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MPASS(ts1 != NULL);
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