sh: Add support Renesas Solutions AP-325RXA board
[linux-2.6/pdupreez.git] / kernel / profile.c
blobcd26bed4cc26535ca7398eae07fb9b800b762f2e
1 /*
2 * linux/kernel/profile.c
3 * Simple profiling. Manages a direct-mapped profile hit count buffer,
4 * with configurable resolution, support for restricting the cpus on
5 * which profiling is done, and switching between cpu time and
6 * schedule() calls via kernel command line parameters passed at boot.
8 * Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
9 * Red Hat, July 2004
10 * Consolidation of architecture support code for profiling,
11 * William Irwin, Oracle, July 2004
12 * Amortized hit count accounting via per-cpu open-addressed hashtables
13 * to resolve timer interrupt livelocks, William Irwin, Oracle, 2004
16 #include <linux/module.h>
17 #include <linux/profile.h>
18 #include <linux/bootmem.h>
19 #include <linux/notifier.h>
20 #include <linux/mm.h>
21 #include <linux/cpumask.h>
22 #include <linux/cpu.h>
23 #include <linux/highmem.h>
24 #include <linux/mutex.h>
25 #include <asm/sections.h>
26 #include <asm/irq_regs.h>
27 #include <asm/ptrace.h>
29 struct profile_hit {
30 u32 pc, hits;
32 #define PROFILE_GRPSHIFT 3
33 #define PROFILE_GRPSZ (1 << PROFILE_GRPSHIFT)
34 #define NR_PROFILE_HIT (PAGE_SIZE/sizeof(struct profile_hit))
35 #define NR_PROFILE_GRP (NR_PROFILE_HIT/PROFILE_GRPSZ)
37 /* Oprofile timer tick hook */
38 static int (*timer_hook)(struct pt_regs *) __read_mostly;
40 static atomic_t *prof_buffer;
41 static unsigned long prof_len, prof_shift;
43 int prof_on __read_mostly;
44 EXPORT_SYMBOL_GPL(prof_on);
46 static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
47 #ifdef CONFIG_SMP
48 static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
49 static DEFINE_PER_CPU(int, cpu_profile_flip);
50 static DEFINE_MUTEX(profile_flip_mutex);
51 #endif /* CONFIG_SMP */
53 static int __init profile_setup(char *str)
55 static char __initdata schedstr[] = "schedule";
56 static char __initdata sleepstr[] = "sleep";
57 static char __initdata kvmstr[] = "kvm";
58 int par;
60 if (!strncmp(str, sleepstr, strlen(sleepstr))) {
61 #ifdef CONFIG_SCHEDSTATS
62 prof_on = SLEEP_PROFILING;
63 if (str[strlen(sleepstr)] == ',')
64 str += strlen(sleepstr) + 1;
65 if (get_option(&str, &par))
66 prof_shift = par;
67 printk(KERN_INFO
68 "kernel sleep profiling enabled (shift: %ld)\n",
69 prof_shift);
70 #else
71 printk(KERN_WARNING
72 "kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
73 #endif /* CONFIG_SCHEDSTATS */
74 } else if (!strncmp(str, schedstr, strlen(schedstr))) {
75 prof_on = SCHED_PROFILING;
76 if (str[strlen(schedstr)] == ',')
77 str += strlen(schedstr) + 1;
78 if (get_option(&str, &par))
79 prof_shift = par;
80 printk(KERN_INFO
81 "kernel schedule profiling enabled (shift: %ld)\n",
82 prof_shift);
83 } else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
84 prof_on = KVM_PROFILING;
85 if (str[strlen(kvmstr)] == ',')
86 str += strlen(kvmstr) + 1;
87 if (get_option(&str, &par))
88 prof_shift = par;
89 printk(KERN_INFO
90 "kernel KVM profiling enabled (shift: %ld)\n",
91 prof_shift);
92 } else if (get_option(&str, &par)) {
93 prof_shift = par;
94 prof_on = CPU_PROFILING;
95 printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
96 prof_shift);
98 return 1;
100 __setup("profile=", profile_setup);
103 void __init profile_init(void)
105 if (!prof_on)
106 return;
108 /* only text is profiled */
109 prof_len = (_etext - _stext) >> prof_shift;
110 prof_buffer = alloc_bootmem(prof_len*sizeof(atomic_t));
113 /* Profile event notifications */
115 static BLOCKING_NOTIFIER_HEAD(task_exit_notifier);
116 static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
117 static BLOCKING_NOTIFIER_HEAD(munmap_notifier);
119 void profile_task_exit(struct task_struct *task)
121 blocking_notifier_call_chain(&task_exit_notifier, 0, task);
124 int profile_handoff_task(struct task_struct *task)
126 int ret;
127 ret = atomic_notifier_call_chain(&task_free_notifier, 0, task);
128 return (ret == NOTIFY_OK) ? 1 : 0;
131 void profile_munmap(unsigned long addr)
133 blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr);
136 int task_handoff_register(struct notifier_block *n)
138 return atomic_notifier_chain_register(&task_free_notifier, n);
140 EXPORT_SYMBOL_GPL(task_handoff_register);
142 int task_handoff_unregister(struct notifier_block *n)
144 return atomic_notifier_chain_unregister(&task_free_notifier, n);
146 EXPORT_SYMBOL_GPL(task_handoff_unregister);
148 int profile_event_register(enum profile_type type, struct notifier_block *n)
150 int err = -EINVAL;
152 switch (type) {
153 case PROFILE_TASK_EXIT:
154 err = blocking_notifier_chain_register(
155 &task_exit_notifier, n);
156 break;
157 case PROFILE_MUNMAP:
158 err = blocking_notifier_chain_register(
159 &munmap_notifier, n);
160 break;
163 return err;
165 EXPORT_SYMBOL_GPL(profile_event_register);
167 int profile_event_unregister(enum profile_type type, struct notifier_block *n)
169 int err = -EINVAL;
171 switch (type) {
172 case PROFILE_TASK_EXIT:
173 err = blocking_notifier_chain_unregister(
174 &task_exit_notifier, n);
175 break;
176 case PROFILE_MUNMAP:
177 err = blocking_notifier_chain_unregister(
178 &munmap_notifier, n);
179 break;
182 return err;
184 EXPORT_SYMBOL_GPL(profile_event_unregister);
186 int register_timer_hook(int (*hook)(struct pt_regs *))
188 if (timer_hook)
189 return -EBUSY;
190 timer_hook = hook;
191 return 0;
193 EXPORT_SYMBOL_GPL(register_timer_hook);
195 void unregister_timer_hook(int (*hook)(struct pt_regs *))
197 WARN_ON(hook != timer_hook);
198 timer_hook = NULL;
199 /* make sure all CPUs see the NULL hook */
200 synchronize_sched(); /* Allow ongoing interrupts to complete. */
202 EXPORT_SYMBOL_GPL(unregister_timer_hook);
205 #ifdef CONFIG_SMP
207 * Each cpu has a pair of open-addressed hashtables for pending
208 * profile hits. read_profile() IPI's all cpus to request them
209 * to flip buffers and flushes their contents to prof_buffer itself.
210 * Flip requests are serialized by the profile_flip_mutex. The sole
211 * use of having a second hashtable is for avoiding cacheline
212 * contention that would otherwise happen during flushes of pending
213 * profile hits required for the accuracy of reported profile hits
214 * and so resurrect the interrupt livelock issue.
216 * The open-addressed hashtables are indexed by profile buffer slot
217 * and hold the number of pending hits to that profile buffer slot on
218 * a cpu in an entry. When the hashtable overflows, all pending hits
219 * are accounted to their corresponding profile buffer slots with
220 * atomic_add() and the hashtable emptied. As numerous pending hits
221 * may be accounted to a profile buffer slot in a hashtable entry,
222 * this amortizes a number of atomic profile buffer increments likely
223 * to be far larger than the number of entries in the hashtable,
224 * particularly given that the number of distinct profile buffer
225 * positions to which hits are accounted during short intervals (e.g.
226 * several seconds) is usually very small. Exclusion from buffer
227 * flipping is provided by interrupt disablement (note that for
228 * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
229 * process context).
230 * The hash function is meant to be lightweight as opposed to strong,
231 * and was vaguely inspired by ppc64 firmware-supported inverted
232 * pagetable hash functions, but uses a full hashtable full of finite
233 * collision chains, not just pairs of them.
235 * -- wli
237 static void __profile_flip_buffers(void *unused)
239 int cpu = smp_processor_id();
241 per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
244 static void profile_flip_buffers(void)
246 int i, j, cpu;
248 mutex_lock(&profile_flip_mutex);
249 j = per_cpu(cpu_profile_flip, get_cpu());
250 put_cpu();
251 on_each_cpu(__profile_flip_buffers, NULL, 1);
252 for_each_online_cpu(cpu) {
253 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
254 for (i = 0; i < NR_PROFILE_HIT; ++i) {
255 if (!hits[i].hits) {
256 if (hits[i].pc)
257 hits[i].pc = 0;
258 continue;
260 atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
261 hits[i].hits = hits[i].pc = 0;
264 mutex_unlock(&profile_flip_mutex);
267 static void profile_discard_flip_buffers(void)
269 int i, cpu;
271 mutex_lock(&profile_flip_mutex);
272 i = per_cpu(cpu_profile_flip, get_cpu());
273 put_cpu();
274 on_each_cpu(__profile_flip_buffers, NULL, 1);
275 for_each_online_cpu(cpu) {
276 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
277 memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
279 mutex_unlock(&profile_flip_mutex);
282 void profile_hits(int type, void *__pc, unsigned int nr_hits)
284 unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
285 int i, j, cpu;
286 struct profile_hit *hits;
288 if (prof_on != type || !prof_buffer)
289 return;
290 pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
291 i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
292 secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
293 cpu = get_cpu();
294 hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
295 if (!hits) {
296 put_cpu();
297 return;
300 * We buffer the global profiler buffer into a per-CPU
301 * queue and thus reduce the number of global (and possibly
302 * NUMA-alien) accesses. The write-queue is self-coalescing:
304 local_irq_save(flags);
305 do {
306 for (j = 0; j < PROFILE_GRPSZ; ++j) {
307 if (hits[i + j].pc == pc) {
308 hits[i + j].hits += nr_hits;
309 goto out;
310 } else if (!hits[i + j].hits) {
311 hits[i + j].pc = pc;
312 hits[i + j].hits = nr_hits;
313 goto out;
316 i = (i + secondary) & (NR_PROFILE_HIT - 1);
317 } while (i != primary);
320 * Add the current hit(s) and flush the write-queue out
321 * to the global buffer:
323 atomic_add(nr_hits, &prof_buffer[pc]);
324 for (i = 0; i < NR_PROFILE_HIT; ++i) {
325 atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
326 hits[i].pc = hits[i].hits = 0;
328 out:
329 local_irq_restore(flags);
330 put_cpu();
333 static int __devinit profile_cpu_callback(struct notifier_block *info,
334 unsigned long action, void *__cpu)
336 int node, cpu = (unsigned long)__cpu;
337 struct page *page;
339 switch (action) {
340 case CPU_UP_PREPARE:
341 case CPU_UP_PREPARE_FROZEN:
342 node = cpu_to_node(cpu);
343 per_cpu(cpu_profile_flip, cpu) = 0;
344 if (!per_cpu(cpu_profile_hits, cpu)[1]) {
345 page = alloc_pages_node(node,
346 GFP_KERNEL | __GFP_ZERO,
348 if (!page)
349 return NOTIFY_BAD;
350 per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);
352 if (!per_cpu(cpu_profile_hits, cpu)[0]) {
353 page = alloc_pages_node(node,
354 GFP_KERNEL | __GFP_ZERO,
356 if (!page)
357 goto out_free;
358 per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);
360 break;
361 out_free:
362 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
363 per_cpu(cpu_profile_hits, cpu)[1] = NULL;
364 __free_page(page);
365 return NOTIFY_BAD;
366 case CPU_ONLINE:
367 case CPU_ONLINE_FROZEN:
368 cpu_set(cpu, prof_cpu_mask);
369 break;
370 case CPU_UP_CANCELED:
371 case CPU_UP_CANCELED_FROZEN:
372 case CPU_DEAD:
373 case CPU_DEAD_FROZEN:
374 cpu_clear(cpu, prof_cpu_mask);
375 if (per_cpu(cpu_profile_hits, cpu)[0]) {
376 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
377 per_cpu(cpu_profile_hits, cpu)[0] = NULL;
378 __free_page(page);
380 if (per_cpu(cpu_profile_hits, cpu)[1]) {
381 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
382 per_cpu(cpu_profile_hits, cpu)[1] = NULL;
383 __free_page(page);
385 break;
387 return NOTIFY_OK;
389 #else /* !CONFIG_SMP */
390 #define profile_flip_buffers() do { } while (0)
391 #define profile_discard_flip_buffers() do { } while (0)
392 #define profile_cpu_callback NULL
394 void profile_hits(int type, void *__pc, unsigned int nr_hits)
396 unsigned long pc;
398 if (prof_on != type || !prof_buffer)
399 return;
400 pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
401 atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
403 #endif /* !CONFIG_SMP */
404 EXPORT_SYMBOL_GPL(profile_hits);
406 void profile_tick(int type)
408 struct pt_regs *regs = get_irq_regs();
410 if (type == CPU_PROFILING && timer_hook)
411 timer_hook(regs);
412 if (!user_mode(regs) && cpu_isset(smp_processor_id(), prof_cpu_mask))
413 profile_hit(type, (void *)profile_pc(regs));
416 #ifdef CONFIG_PROC_FS
417 #include <linux/proc_fs.h>
418 #include <asm/uaccess.h>
419 #include <asm/ptrace.h>
421 static int prof_cpu_mask_read_proc(char *page, char **start, off_t off,
422 int count, int *eof, void *data)
424 int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
425 if (count - len < 2)
426 return -EINVAL;
427 len += sprintf(page + len, "\n");
428 return len;
431 static int prof_cpu_mask_write_proc(struct file *file,
432 const char __user *buffer, unsigned long count, void *data)
434 cpumask_t *mask = (cpumask_t *)data;
435 unsigned long full_count = count, err;
436 cpumask_t new_value;
438 err = cpumask_parse_user(buffer, count, new_value);
439 if (err)
440 return err;
442 *mask = new_value;
443 return full_count;
446 void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir)
448 struct proc_dir_entry *entry;
450 /* create /proc/irq/prof_cpu_mask */
451 entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
452 if (!entry)
453 return;
454 entry->data = (void *)&prof_cpu_mask;
455 entry->read_proc = prof_cpu_mask_read_proc;
456 entry->write_proc = prof_cpu_mask_write_proc;
460 * This function accesses profiling information. The returned data is
461 * binary: the sampling step and the actual contents of the profile
462 * buffer. Use of the program readprofile is recommended in order to
463 * get meaningful info out of these data.
465 static ssize_t
466 read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
468 unsigned long p = *ppos;
469 ssize_t read;
470 char *pnt;
471 unsigned int sample_step = 1 << prof_shift;
473 profile_flip_buffers();
474 if (p >= (prof_len+1)*sizeof(unsigned int))
475 return 0;
476 if (count > (prof_len+1)*sizeof(unsigned int) - p)
477 count = (prof_len+1)*sizeof(unsigned int) - p;
478 read = 0;
480 while (p < sizeof(unsigned int) && count > 0) {
481 if (put_user(*((char *)(&sample_step)+p), buf))
482 return -EFAULT;
483 buf++; p++; count--; read++;
485 pnt = (char *)prof_buffer + p - sizeof(atomic_t);
486 if (copy_to_user(buf, (void *)pnt, count))
487 return -EFAULT;
488 read += count;
489 *ppos += read;
490 return read;
494 * Writing to /proc/profile resets the counters
496 * Writing a 'profiling multiplier' value into it also re-sets the profiling
497 * interrupt frequency, on architectures that support this.
499 static ssize_t write_profile(struct file *file, const char __user *buf,
500 size_t count, loff_t *ppos)
502 #ifdef CONFIG_SMP
503 extern int setup_profiling_timer(unsigned int multiplier);
505 if (count == sizeof(int)) {
506 unsigned int multiplier;
508 if (copy_from_user(&multiplier, buf, sizeof(int)))
509 return -EFAULT;
511 if (setup_profiling_timer(multiplier))
512 return -EINVAL;
514 #endif
515 profile_discard_flip_buffers();
516 memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
517 return count;
520 static const struct file_operations proc_profile_operations = {
521 .read = read_profile,
522 .write = write_profile,
525 #ifdef CONFIG_SMP
526 static void __init profile_nop(void *unused)
530 static int __init create_hash_tables(void)
532 int cpu;
534 for_each_online_cpu(cpu) {
535 int node = cpu_to_node(cpu);
536 struct page *page;
538 page = alloc_pages_node(node,
539 GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
541 if (!page)
542 goto out_cleanup;
543 per_cpu(cpu_profile_hits, cpu)[1]
544 = (struct profile_hit *)page_address(page);
545 page = alloc_pages_node(node,
546 GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
548 if (!page)
549 goto out_cleanup;
550 per_cpu(cpu_profile_hits, cpu)[0]
551 = (struct profile_hit *)page_address(page);
553 return 0;
554 out_cleanup:
555 prof_on = 0;
556 smp_mb();
557 on_each_cpu(profile_nop, NULL, 1);
558 for_each_online_cpu(cpu) {
559 struct page *page;
561 if (per_cpu(cpu_profile_hits, cpu)[0]) {
562 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
563 per_cpu(cpu_profile_hits, cpu)[0] = NULL;
564 __free_page(page);
566 if (per_cpu(cpu_profile_hits, cpu)[1]) {
567 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
568 per_cpu(cpu_profile_hits, cpu)[1] = NULL;
569 __free_page(page);
572 return -1;
574 #else
575 #define create_hash_tables() ({ 0; })
576 #endif
578 static int __init create_proc_profile(void)
580 struct proc_dir_entry *entry;
582 if (!prof_on)
583 return 0;
584 if (create_hash_tables())
585 return -1;
586 entry = proc_create("profile", S_IWUSR | S_IRUGO,
587 NULL, &proc_profile_operations);
588 if (!entry)
589 return 0;
590 entry->size = (1+prof_len) * sizeof(atomic_t);
591 hotcpu_notifier(profile_cpu_callback, 0);
592 return 0;
594 module_init(create_proc_profile);
595 #endif /* CONFIG_PROC_FS */