Backout experimental adaptive-spin umtx code.

9 files changed, 1 insertions, 77 deletions

diff --git a/sys/amd64/amd64/cpu_switch.S b/sys/amd64/amd64/cpu_switch.S
index 79a9f91..2d65667 100644
--- a/sys/amd64/amd64/cpu_switch.S
+++ b/sys/amd64/amd64/cpu_switch.S
@@ -203,9 +203,7 @@ sw1:
 	movq	%rbx, (%rax)
 	movq	%rbx, PCPU(RSP0)
 
-	movl	TD_TID(%rsi), %eax
 	movq	%r8, PCPU(CURPCB)
-	movl	%eax, PCPU(CURTID)
 	movq	%rsi, PCPU(CURTHREAD)		/* into next thread */
 
 	testl	$PCB_32BIT,PCB_FLAGS(%r8)
diff --git a/sys/amd64/amd64/genassym.c b/sys/amd64/amd64/genassym.c
index bed8b53..42858b3 100644
--- a/sys/amd64/amd64/genassym.c
+++ b/sys/amd64/amd64/genassym.c
@@ -194,7 +194,6 @@ ASSYM(PC_SCRATCH_RSP, offsetof(struct pcpu, pc_scratch_rsp));
 ASSYM(PC_CURPMAP, offsetof(struct pcpu, pc_curpmap));
 ASSYM(PC_TSSP, offsetof(struct pcpu, pc_tssp));
 ASSYM(PC_RSP0, offsetof(struct pcpu, pc_rsp0));
-ASSYM(PC_CURTID, offsetof(struct pcpu, pc_curtid));
  
 ASSYM(LA_VER, offsetof(struct LAPIC, version));
 ASSYM(LA_TPR, offsetof(struct LAPIC, tpr));
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index a52ea51..7252386 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1179,7 +1179,6 @@ hammer_time(u_int64_t modulep, u_int64_t physfree)
 	PCPU_SET(prvspace, pc);
 	PCPU_SET(curthread, &thread0);
 	PCPU_SET(curpcb, thread0.td_pcb);
-	PCPU_SET(curtid, thread0.td_tid);
 	PCPU_SET(tssp, &common_tss[0]);
 
 	/*
diff --git a/sys/i386/i386/genassym.c b/sys/i386/i386/genassym.c
index bf15298..791bf09 100644
--- a/sys/i386/i386/genassym.c
+++ b/sys/i386/i386/genassym.c
@@ -199,7 +199,6 @@ ASSYM(PC_CURRENTLDT, offsetof(struct pcpu, pc_currentldt));
 ASSYM(PC_CPUID, offsetof(struct pcpu, pc_cpuid));
 ASSYM(PC_CURPMAP, offsetof(struct pcpu, pc_curpmap));
 ASSYM(PC_PRIVATE_TSS, offsetof(struct pcpu, pc_private_tss));
-ASSYM(PC_CURTID, offsetof(struct pcpu, pc_curtid));
 
 #ifdef DEV_APIC
 ASSYM(LA_VER, offsetof(struct LAPIC, version));
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 16f2303..df3b5eb 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -2118,7 +2118,6 @@ init386(first)
 	PCPU_SET(prvspace, pc);
 	PCPU_SET(curthread, &thread0);
 	PCPU_SET(curpcb, thread0.td_pcb);
-	PCPU_SET(curtid, thread0.td_tid);
 
 	/*
 	 * Initialize mutexes.
diff --git a/sys/i386/i386/swtch.s b/sys/i386/i386/swtch.s
index 5df5959..9002a81 100644
--- a/sys/i386/i386/swtch.s
+++ b/sys/i386/i386/swtch.s
@@ -247,7 +247,6 @@ sw1:
 	movl	%edx, PCPU(CURPCB)
 	movl	TD_TID(%ecx),%eax
 	movl	%ecx, PCPU(CURTHREAD)		/* into next thread */
-	movl	%eax, PCPU(CURTID)
 
 	/*
 	 * Determine the LDT to use and load it if is the default one and
diff --git a/sys/kern/kern_umtx.c b/sys/kern/kern_umtx.c
index 2640278..6df3ce7 100644
--- a/sys/kern/kern_umtx.c
+++ b/sys/kern/kern_umtx.c
@@ -193,13 +193,6 @@ static int			umtx_pi_allocated;
 SYSCTL_NODE(_debug, OID_AUTO, umtx, CTLFLAG_RW, 0, "umtx debug");
 SYSCTL_INT(_debug_umtx, OID_AUTO, umtx_pi_allocated, CTLFLAG_RD,
     &umtx_pi_allocated, 0, "Allocated umtx_pi");
-SYSCTL_DECL(_kern_threads);
-static int			umtx_dflt_spins = 0;
-SYSCTL_INT(_kern_threads, OID_AUTO, umtx_dflt_spins, CTLFLAG_RW,
-    &umtx_dflt_spins, 0, "default umtx spin count");
-static int			umtx_max_spins = 3000;
-SYSCTL_INT(_kern_threads, OID_AUTO, umtx_max_spins, CTLFLAG_RW,
-    &umtx_max_spins, 0, "max umtx spin count");
 
 static void umtxq_sysinit(void *);
 static void umtxq_hash(struct umtx_key *key);
@@ -1025,33 +1018,16 @@ _do_lock_normal(struct thread *td, struct umutex *m, uint32_t flags, int timo,
 {
 	struct umtx_q *uq;
 	uint32_t owner, old, id;
-#ifdef SMP
-	int spincount;
-#endif
 	int error = 0;
 
 	id = td->td_tid;
 	uq = td->td_umtxq;
 
-#ifdef SMP
-	if (smp_cpus > 1) {
-		spincount = fuword32(&m->m_spincount);
-		if (spincount == 0)
-			spincount = umtx_dflt_spins;
-		if (spincount > umtx_max_spins)
-			spincount = umtx_max_spins;
-	} else
-		spincount = 0;
-#endif
-
 	/*
 	 * Care must be exercised when dealing with umtx structure. It
 	 * can fault on any access.
 	 */
 	for (;;) {
-#ifdef SMP
-try_unowned:
-#endif
 		/*
 		 * Try the uncontested case.  This should be done in userland.
 		 */
@@ -1067,9 +1043,6 @@ try_unowned:
 
 		/* If no one owns it but it is contested try to acquire it. */
 		if (owner == UMUTEX_CONTESTED) {
-#ifdef SMP
-try_contested:
-#endif
 			owner = casuword32(&m->m_owner,
 			    UMUTEX_CONTESTED, id | UMUTEX_CONTESTED);
 
@@ -1091,46 +1064,6 @@ try_contested:
 		if (try != 0)
 			return (EBUSY);
 
-#ifdef SMP
-		if (spincount > 0 && (owner & ~UMUTEX_CONTESTED) != id) {
-			int i, found = 0;
-			struct pcpu *pcpu = NULL;
-
-			/* Look for a cpu the owner is running on */
-			for (i = 0; i < MAXCPU; i++) {
-				if (CPU_ABSENT(i))
-					continue;
-				pcpu = pcpu_find(i);
-				if ((owner & ~UMUTEX_CONTESTED) == pcpu->pc_curtid) {
-					found = 1;
-					break;
-				}
-			}
-
-			if (__predict_false(!found))
-				goto end_spin;
-
-			while ((owner & ~UMUTEX_CONTESTED) == pcpu->pc_curtid &&
-			       (owner & ~UMUTEX_CONTESTED) != id) {
-				if (--spincount <= 0)
-					break;
-				if ((td->td_flags &
-			    	    (TDF_NEEDRESCHED|TDF_ASTPENDING|TDF_NEEDSIGCHK)) ||
-				     P_SHOULDSTOP(td->td_proc))
-					break;
-				owner = fuword32(__DEVOLATILE(uint32_t *, &m->m_owner));
-				if (owner == UMUTEX_UNOWNED)
-					goto try_unowned;
- 				if (owner == UMUTEX_CONTESTED)
-					goto try_contested;
-				cpu_spinwait();
-			}
-		}
-end_spin:
-		spincount = 0;
-
-#endif
-
 		/*
 		 * If we caught a signal, we have retried and now
 		 * exit immediately.
diff --git a/sys/sys/pcpu.h b/sys/sys/pcpu.h
index 1e415c3..b2fd628 100644
--- a/sys/sys/pcpu.h
+++ b/sys/sys/pcpu.h
@@ -74,7 +74,6 @@ struct pcpu {
 	PCPU_MD_FIELDS;
 	struct vmmeter	pc_cnt;			/* VM stats counters */
 	struct device	*pc_device;
-	lwpid_t		pc_curtid;
 };
 
 SLIST_HEAD(cpuhead, pcpu);
diff --git a/sys/sys/umtx.h b/sys/sys/umtx.h
index eaea8f6..6631be7 100644
--- a/sys/sys/umtx.h
+++ b/sys/sys/umtx.h
@@ -57,8 +57,7 @@ struct umutex {
 	volatile __lwpid_t	m_owner;	/* Owner of the mutex */
 	uint32_t		m_flags;	/* Flags of the mutex */
 	uint32_t		m_ceilings[2];	/* Priority protect ceiling */
-	uint32_t		m_spincount;	/* Max spinning cycle */
-	uint32_t		m_spare[3];
+	uint32_t		m_spare[4];
 };
 
 struct ucond {