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authorTony Luck <tony.luck@intel.com>2005-05-18 19:06:00 -0400
committerTony Luck <tony.luck@intel.com>2005-05-18 19:14:30 -0400
commita1ecf7f6e65637ba4470405ad39794710dbf85d4 (patch)
treea086e2ba8bf56c398c6d50a47d91af6d977aaf63 /arch/ia64/kernel/perfmon.c
parent6872ec548970e9fb3ccd61013f84f9bb8b30fa9a (diff)
[IA64] alternate perfmon handler
Patch from Charles Spirakis Some linux customers want to optimize their applications on the latest hardware but are not yet willing to upgrade to the latest kernel. This patch provides a way to plug in an alternate, basic, and GPL'ed PMU subsystem to help with their monitoring needs or for specialty work. It can also be used in case of serious unexpected bugs in perfmon. Mutual exclusion between the two subsystems is guaranteed, hence no conflict can arise from both subsystem being present. Acked-by: Stephane Eranian <eranian@hpl.hp.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/kernel/perfmon.c')
-rw-r--r--arch/ia64/kernel/perfmon.c175
1 files changed, 160 insertions, 15 deletions
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 71c101601e3e..ab9682f8b044 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -11,7 +11,7 @@
11 * Version Perfmon-2.x is a rewrite of perfmon-1.x 11 * Version Perfmon-2.x is a rewrite of perfmon-1.x
12 * by Stephane Eranian, Hewlett Packard Co. 12 * by Stephane Eranian, Hewlett Packard Co.
13 * 13 *
14 * Copyright (C) 1999-2003, 2005 Hewlett Packard Co 14 * Copyright (C) 1999-2005 Hewlett Packard Co
15 * Stephane Eranian <eranian@hpl.hp.com> 15 * Stephane Eranian <eranian@hpl.hp.com>
16 * David Mosberger-Tang <davidm@hpl.hp.com> 16 * David Mosberger-Tang <davidm@hpl.hp.com>
17 * 17 *
@@ -497,6 +497,9 @@ typedef struct {
497static pfm_stats_t pfm_stats[NR_CPUS]; 497static pfm_stats_t pfm_stats[NR_CPUS];
498static pfm_session_t pfm_sessions; /* global sessions information */ 498static pfm_session_t pfm_sessions; /* global sessions information */
499 499
500static spinlock_t pfm_alt_install_check;
501static pfm_intr_handler_desc_t *pfm_alt_intr_handler;
502
500static struct proc_dir_entry *perfmon_dir; 503static struct proc_dir_entry *perfmon_dir;
501static pfm_uuid_t pfm_null_uuid = {0,}; 504static pfm_uuid_t pfm_null_uuid = {0,};
502 505
@@ -606,6 +609,7 @@ DEFINE_PER_CPU(unsigned long, pfm_syst_info);
606DEFINE_PER_CPU(struct task_struct *, pmu_owner); 609DEFINE_PER_CPU(struct task_struct *, pmu_owner);
607DEFINE_PER_CPU(pfm_context_t *, pmu_ctx); 610DEFINE_PER_CPU(pfm_context_t *, pmu_ctx);
608DEFINE_PER_CPU(unsigned long, pmu_activation_number); 611DEFINE_PER_CPU(unsigned long, pmu_activation_number);
612EXPORT_SYMBOL_GPL(per_cpu__pfm_syst_info);
609 613
610 614
611/* forward declaration */ 615/* forward declaration */
@@ -1325,7 +1329,7 @@ pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
1325error_conflict: 1329error_conflict:
1326 DPRINT(("system wide not possible, conflicting session [%d] on CPU%d\n", 1330 DPRINT(("system wide not possible, conflicting session [%d] on CPU%d\n",
1327 pfm_sessions.pfs_sys_session[cpu]->pid, 1331 pfm_sessions.pfs_sys_session[cpu]->pid,
1328 smp_processor_id())); 1332 cpu));
1329abort: 1333abort:
1330 UNLOCK_PFS(flags); 1334 UNLOCK_PFS(flags);
1331 1335
@@ -5555,26 +5559,32 @@ pfm_interrupt_handler(int irq, void *arg, struct pt_regs *regs)
5555 int ret; 5559 int ret;
5556 5560
5557 this_cpu = get_cpu(); 5561 this_cpu = get_cpu();
5558 min = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min; 5562 if (likely(!pfm_alt_intr_handler)) {
5559 max = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max; 5563 min = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min;
5564 max = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max;
5560 5565
5561 start_cycles = ia64_get_itc(); 5566 start_cycles = ia64_get_itc();
5562 5567
5563 ret = pfm_do_interrupt_handler(irq, arg, regs); 5568 ret = pfm_do_interrupt_handler(irq, arg, regs);
5564 5569
5565 total_cycles = ia64_get_itc(); 5570 total_cycles = ia64_get_itc();
5566 5571
5567 /* 5572 /*
5568 * don't measure spurious interrupts 5573 * don't measure spurious interrupts
5569 */ 5574 */
5570 if (likely(ret == 0)) { 5575 if (likely(ret == 0)) {
5571 total_cycles -= start_cycles; 5576 total_cycles -= start_cycles;
5572 5577
5573 if (total_cycles < min) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min = total_cycles; 5578 if (total_cycles < min) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min = total_cycles;
5574 if (total_cycles > max) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max = total_cycles; 5579 if (total_cycles > max) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max = total_cycles;
5575 5580
5576 pfm_stats[this_cpu].pfm_ovfl_intr_cycles += total_cycles; 5581 pfm_stats[this_cpu].pfm_ovfl_intr_cycles += total_cycles;
5582 }
5583 }
5584 else {
5585 (*pfm_alt_intr_handler->handler)(irq, arg, regs);
5577 } 5586 }
5587
5578 put_cpu_no_resched(); 5588 put_cpu_no_resched();
5579 return IRQ_HANDLED; 5589 return IRQ_HANDLED;
5580} 5590}
@@ -6425,6 +6435,141 @@ static struct irqaction perfmon_irqaction = {
6425 .name = "perfmon" 6435 .name = "perfmon"
6426}; 6436};
6427 6437
6438static void
6439pfm_alt_save_pmu_state(void *data)
6440{
6441 struct pt_regs *regs;
6442
6443 regs = ia64_task_regs(current);
6444
6445 DPRINT(("called\n"));
6446
6447 /*
6448 * should not be necessary but
6449 * let's take not risk
6450 */
6451 pfm_clear_psr_up();
6452 pfm_clear_psr_pp();
6453 ia64_psr(regs)->pp = 0;
6454
6455 /*
6456 * This call is required
6457 * May cause a spurious interrupt on some processors
6458 */
6459 pfm_freeze_pmu();
6460
6461 ia64_srlz_d();
6462}
6463
6464void
6465pfm_alt_restore_pmu_state(void *data)
6466{
6467 struct pt_regs *regs;
6468
6469 regs = ia64_task_regs(current);
6470
6471 DPRINT(("called\n"));
6472
6473 /*
6474 * put PMU back in state expected
6475 * by perfmon
6476 */
6477 pfm_clear_psr_up();
6478 pfm_clear_psr_pp();
6479 ia64_psr(regs)->pp = 0;
6480
6481 /*
6482 * perfmon runs with PMU unfrozen at all times
6483 */
6484 pfm_unfreeze_pmu();
6485
6486 ia64_srlz_d();
6487}
6488
6489int
6490pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
6491{
6492 int ret, i;
6493 int reserve_cpu;
6494
6495 /* some sanity checks */
6496 if (hdl == NULL || hdl->handler == NULL) return -EINVAL;
6497
6498 /* do the easy test first */
6499 if (pfm_alt_intr_handler) return -EBUSY;
6500
6501 /* one at a time in the install or remove, just fail the others */
6502 if (!spin_trylock(&pfm_alt_install_check)) {
6503 return -EBUSY;
6504 }
6505
6506 /* reserve our session */
6507 for_each_online_cpu(reserve_cpu) {
6508 ret = pfm_reserve_session(NULL, 1, reserve_cpu);
6509 if (ret) goto cleanup_reserve;
6510 }
6511
6512 /* save the current system wide pmu states */
6513 ret = on_each_cpu(pfm_alt_save_pmu_state, NULL, 0, 1);
6514 if (ret) {
6515 DPRINT(("on_each_cpu() failed: %d\n", ret));
6516 goto cleanup_reserve;
6517 }
6518
6519 /* officially change to the alternate interrupt handler */
6520 pfm_alt_intr_handler = hdl;
6521
6522 spin_unlock(&pfm_alt_install_check);
6523
6524 return 0;
6525
6526cleanup_reserve:
6527 for_each_online_cpu(i) {
6528 /* don't unreserve more than we reserved */
6529 if (i >= reserve_cpu) break;
6530
6531 pfm_unreserve_session(NULL, 1, i);
6532 }
6533
6534 spin_unlock(&pfm_alt_install_check);
6535
6536 return ret;
6537}
6538EXPORT_SYMBOL_GPL(pfm_install_alt_pmu_interrupt);
6539
6540int
6541pfm_remove_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
6542{
6543 int i;
6544 int ret;
6545
6546 if (hdl == NULL) return -EINVAL;
6547
6548 /* cannot remove someone else's handler! */
6549 if (pfm_alt_intr_handler != hdl) return -EINVAL;
6550
6551 /* one at a time in the install or remove, just fail the others */
6552 if (!spin_trylock(&pfm_alt_install_check)) {
6553 return -EBUSY;
6554 }
6555
6556 pfm_alt_intr_handler = NULL;
6557
6558 ret = on_each_cpu(pfm_alt_restore_pmu_state, NULL, 0, 1);
6559 if (ret) {
6560 DPRINT(("on_each_cpu() failed: %d\n", ret));
6561 }
6562
6563 for_each_online_cpu(i) {
6564 pfm_unreserve_session(NULL, 1, i);
6565 }
6566
6567 spin_unlock(&pfm_alt_install_check);
6568
6569 return 0;
6570}
6571EXPORT_SYMBOL_GPL(pfm_remove_alt_pmu_interrupt);
6572
6428/* 6573/*
6429 * perfmon initialization routine, called from the initcall() table 6574 * perfmon initialization routine, called from the initcall() table
6430 */ 6575 */