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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2010-03-02 10:01:10 -0500
committerRobert Richter <robert.richter@amd.com>2010-03-02 11:03:20 -0500
commitbc078e4eab65f11bbaeed380593ab8151b30d703 (patch)
tree8d61457355fad4e5b5938cd7c01a1dd379778789 /drivers/oprofile
parentcfc9c0b450176a077205ef39092f0dc1a04e020a (diff)
oprofile: convert oprofile from timer_hook to hrtimer
Oprofile is currently broken on systems running with NOHZ enabled. A maximum of 1 tick is accounted via the timer_hook if a cpu sleeps for a longer period of time. This does bad things to the percentages in the profiler output. To solve this problem convert oprofile to use a restarting hrtimer instead of the timer_hook. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
Diffstat (limited to 'drivers/oprofile')
-rw-r--r--drivers/oprofile/oprof.c12
-rw-r--r--drivers/oprofile/oprof.h3
-rw-r--r--drivers/oprofile/timer_int.c78
3 files changed, 79 insertions, 14 deletions
diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c
index dc8a0428260d..b336cd9ee7a1 100644
--- a/drivers/oprofile/oprof.c
+++ b/drivers/oprofile/oprof.c
@@ -253,22 +253,26 @@ static int __init oprofile_init(void)
253 int err; 253 int err;
254 254
255 err = oprofile_arch_init(&oprofile_ops); 255 err = oprofile_arch_init(&oprofile_ops);
256
257 if (err < 0 || timer) { 256 if (err < 0 || timer) {
258 printk(KERN_INFO "oprofile: using timer interrupt.\n"); 257 printk(KERN_INFO "oprofile: using timer interrupt.\n");
259 oprofile_timer_init(&oprofile_ops); 258 err = oprofile_timer_init(&oprofile_ops);
259 if (err)
260 goto out_arch;
260 } 261 }
261
262 err = oprofilefs_register(); 262 err = oprofilefs_register();
263 if (err) 263 if (err)
264 oprofile_arch_exit(); 264 goto out_arch;
265 return 0;
265 266
267out_arch:
268 oprofile_arch_exit();
266 return err; 269 return err;
267} 270}
268 271
269 272
270static void __exit oprofile_exit(void) 273static void __exit oprofile_exit(void)
271{ 274{
275 oprofile_timer_exit();
272 oprofilefs_unregister(); 276 oprofilefs_unregister();
273 oprofile_arch_exit(); 277 oprofile_arch_exit();
274} 278}
diff --git a/drivers/oprofile/oprof.h b/drivers/oprofile/oprof.h
index cb92f5c98c1a..47e12cb4ee8b 100644
--- a/drivers/oprofile/oprof.h
+++ b/drivers/oprofile/oprof.h
@@ -34,7 +34,8 @@ struct super_block;
34struct dentry; 34struct dentry;
35 35
36void oprofile_create_files(struct super_block *sb, struct dentry *root); 36void oprofile_create_files(struct super_block *sb, struct dentry *root);
37void oprofile_timer_init(struct oprofile_operations *ops); 37int oprofile_timer_init(struct oprofile_operations *ops);
38void oprofile_timer_exit(void);
38 39
39int oprofile_set_backtrace(unsigned long depth); 40int oprofile_set_backtrace(unsigned long depth);
40int oprofile_set_timeout(unsigned long time); 41int oprofile_set_timeout(unsigned long time);
diff --git a/drivers/oprofile/timer_int.c b/drivers/oprofile/timer_int.c
index 333f915568c7..dc0ae4d14dff 100644
--- a/drivers/oprofile/timer_int.c
+++ b/drivers/oprofile/timer_int.c
@@ -13,34 +13,94 @@
13#include <linux/oprofile.h> 13#include <linux/oprofile.h>
14#include <linux/profile.h> 14#include <linux/profile.h>
15#include <linux/init.h> 15#include <linux/init.h>
16#include <linux/cpu.h>
17#include <linux/hrtimer.h>
18#include <asm/irq_regs.h>
16#include <asm/ptrace.h> 19#include <asm/ptrace.h>
17 20
18#include "oprof.h" 21#include "oprof.h"
19 22
20static int timer_notify(struct pt_regs *regs) 23static DEFINE_PER_CPU(struct hrtimer, oprofile_hrtimer);
24
25static enum hrtimer_restart oprofile_hrtimer_notify(struct hrtimer *hrtimer)
26{
27 oprofile_add_sample(get_irq_regs(), 0);
28 hrtimer_forward_now(hrtimer, ns_to_ktime(TICK_NSEC));
29 return HRTIMER_RESTART;
30}
31
32static void __oprofile_hrtimer_start(void *unused)
33{
34 struct hrtimer *hrtimer = &__get_cpu_var(oprofile_hrtimer);
35
36 hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
37 hrtimer->function = oprofile_hrtimer_notify;
38
39 hrtimer_start(hrtimer, ns_to_ktime(TICK_NSEC),
40 HRTIMER_MODE_REL_PINNED);
41}
42
43static int oprofile_hrtimer_start(void)
21{ 44{
22 oprofile_add_sample(regs, 0); 45 on_each_cpu(__oprofile_hrtimer_start, NULL, 1);
23 return 0; 46 return 0;
24} 47}
25 48
26static int timer_start(void) 49static void __oprofile_hrtimer_stop(int cpu)
27{ 50{
28 return register_timer_hook(timer_notify); 51 struct hrtimer *hrtimer = &per_cpu(oprofile_hrtimer, cpu);
52
53 hrtimer_cancel(hrtimer);
29} 54}
30 55
56static void oprofile_hrtimer_stop(void)
57{
58 int cpu;
59
60 for_each_online_cpu(cpu)
61 __oprofile_hrtimer_stop(cpu);
62}
31 63
32static void timer_stop(void) 64static int __cpuinit oprofile_cpu_notify(struct notifier_block *self,
65 unsigned long action, void *hcpu)
33{ 66{
34 unregister_timer_hook(timer_notify); 67 long cpu = (long) hcpu;
68
69 switch (action) {
70 case CPU_ONLINE:
71 case CPU_ONLINE_FROZEN:
72 smp_call_function_single(cpu, __oprofile_hrtimer_start,
73 NULL, 1);
74 break;
75 case CPU_DEAD:
76 case CPU_DEAD_FROZEN:
77 __oprofile_hrtimer_stop(cpu);
78 break;
79 }
80 return NOTIFY_OK;
35} 81}
36 82
83static struct notifier_block __refdata oprofile_cpu_notifier = {
84 .notifier_call = oprofile_cpu_notify,
85};
37 86
38void __init oprofile_timer_init(struct oprofile_operations *ops) 87int __init oprofile_timer_init(struct oprofile_operations *ops)
39{ 88{
89 int rc;
90
91 rc = register_hotcpu_notifier(&oprofile_cpu_notifier);
92 if (rc)
93 return rc;
40 ops->create_files = NULL; 94 ops->create_files = NULL;
41 ops->setup = NULL; 95 ops->setup = NULL;
42 ops->shutdown = NULL; 96 ops->shutdown = NULL;
43 ops->start = timer_start; 97 ops->start = oprofile_hrtimer_start;
44 ops->stop = timer_stop; 98 ops->stop = oprofile_hrtimer_stop;
45 ops->cpu_type = "timer"; 99 ops->cpu_type = "timer";
100 return 0;
101}
102
103void __exit oprofile_timer_exit(void)
104{
105 unregister_hotcpu_notifier(&oprofile_cpu_notifier);
46} 106}