| /* |
| * unlikely profiler |
| * |
| * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com> |
| */ |
| #include <linux/kallsyms.h> |
| #include <linux/seq_file.h> |
| #include <linux/spinlock.h> |
| #include <linux/irqflags.h> |
| #include <linux/debugfs.h> |
| #include <linux/uaccess.h> |
| #include <linux/module.h> |
| #include <linux/ftrace.h> |
| #include <linux/hash.h> |
| #include <linux/fs.h> |
| #include <asm/local.h> |
| |
| #include "trace.h" |
| #include "trace_stat.h" |
| #include "trace_output.h" |
| |
| #ifdef CONFIG_BRANCH_TRACER |
| |
| static struct tracer branch_trace; |
| static int branch_tracing_enabled __read_mostly; |
| static DEFINE_MUTEX(branch_tracing_mutex); |
| |
| static struct trace_array *branch_tracer; |
| |
| static void |
| probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) |
| { |
| struct ftrace_event_call *call = &event_branch; |
| struct trace_array *tr = branch_tracer; |
| struct ring_buffer_event *event; |
| struct trace_branch *entry; |
| struct ring_buffer *buffer; |
| unsigned long flags; |
| int cpu, pc; |
| const char *p; |
| |
| /* |
| * I would love to save just the ftrace_likely_data pointer, but |
| * this code can also be used by modules. Ugly things can happen |
| * if the module is unloaded, and then we go and read the |
| * pointer. This is slower, but much safer. |
| */ |
| |
| if (unlikely(!tr)) |
| return; |
| |
| local_irq_save(flags); |
| cpu = raw_smp_processor_id(); |
| if (atomic_inc_return(&tr->data[cpu]->disabled) != 1) |
| goto out; |
| |
| pc = preempt_count(); |
| buffer = tr->buffer; |
| event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH, |
| sizeof(*entry), flags, pc); |
| if (!event) |
| goto out; |
| |
| entry = ring_buffer_event_data(event); |
| |
| /* Strip off the path, only save the file */ |
| p = f->file + strlen(f->file); |
| while (p >= f->file && *p != '/') |
| p--; |
| p++; |
| |
| strncpy(entry->func, f->func, TRACE_FUNC_SIZE); |
| strncpy(entry->file, p, TRACE_FILE_SIZE); |
| entry->func[TRACE_FUNC_SIZE] = 0; |
| entry->file[TRACE_FILE_SIZE] = 0; |
| entry->line = f->line; |
| entry->correct = val == expect; |
| |
| if (!filter_check_discard(call, entry, buffer, event)) |
| ring_buffer_unlock_commit(buffer, event); |
| |
| out: |
| atomic_dec(&tr->data[cpu]->disabled); |
| local_irq_restore(flags); |
| } |
| |
| static inline |
| void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) |
| { |
| if (!branch_tracing_enabled) |
| return; |
| |
| probe_likely_condition(f, val, expect); |
| } |
| |
| int enable_branch_tracing(struct trace_array *tr) |
| { |
| mutex_lock(&branch_tracing_mutex); |
| branch_tracer = tr; |
| /* |
| * Must be seen before enabling. The reader is a condition |
| * where we do not need a matching rmb() |
| */ |
| smp_wmb(); |
| branch_tracing_enabled++; |
| mutex_unlock(&branch_tracing_mutex); |
| |
| return 0; |
| } |
| |
| void disable_branch_tracing(void) |
| { |
| mutex_lock(&branch_tracing_mutex); |
| |
| if (!branch_tracing_enabled) |
| goto out_unlock; |
| |
| branch_tracing_enabled--; |
| |
| out_unlock: |
| mutex_unlock(&branch_tracing_mutex); |
| } |
| |
| static void start_branch_trace(struct trace_array *tr) |
| { |
| enable_branch_tracing(tr); |
| } |
| |
| static void stop_branch_trace(struct trace_array *tr) |
| { |
| disable_branch_tracing(); |
| } |
| |
| static int branch_trace_init(struct trace_array *tr) |
| { |
| start_branch_trace(tr); |
| return 0; |
| } |
| |
| static void branch_trace_reset(struct trace_array *tr) |
| { |
| stop_branch_trace(tr); |
| } |
| |
| static enum print_line_t trace_branch_print(struct trace_iterator *iter, |
| int flags, struct trace_event *event) |
| { |
| struct trace_branch *field; |
| |
| trace_assign_type(field, iter->ent); |
| |
| if (trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n", |
| field->correct ? " ok " : " MISS ", |
| field->func, |
| field->file, |
| field->line)) |
| return TRACE_TYPE_PARTIAL_LINE; |
| |
| return TRACE_TYPE_HANDLED; |
| } |
| |
| static void branch_print_header(struct seq_file *s) |
| { |
| seq_puts(s, "# TASK-PID CPU# TIMESTAMP CORRECT" |
| " FUNC:FILE:LINE\n"); |
| seq_puts(s, "# | | | | | " |
| " |\n"); |
| } |
| |
| static struct trace_event_functions trace_branch_funcs = { |
| .trace = trace_branch_print, |
| }; |
| |
| static struct trace_event trace_branch_event = { |
| .type = TRACE_BRANCH, |
| .funcs = &trace_branch_funcs, |
| }; |
| |
| static struct tracer branch_trace __read_mostly = |
| { |
| .name = "branch", |
| .init = branch_trace_init, |
| .reset = branch_trace_reset, |
| #ifdef CONFIG_FTRACE_SELFTEST |
| .selftest = trace_selftest_startup_branch, |
| #endif /* CONFIG_FTRACE_SELFTEST */ |
| .print_header = branch_print_header, |
| }; |
| |
| __init static int init_branch_tracer(void) |
| { |
| int ret; |
| |
| ret = register_ftrace_event(&trace_branch_event); |
| if (!ret) { |
| printk(KERN_WARNING "Warning: could not register " |
| "branch events\n"); |
| return 1; |
| } |
| return register_tracer(&branch_trace); |
| } |
| device_initcall(init_branch_tracer); |
| |
| #else |
| static inline |
| void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) |
| { |
| } |
| #endif /* CONFIG_BRANCH_TRACER */ |
| |
| void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect) |
| { |
| /* |
| * I would love to have a trace point here instead, but the |
| * trace point code is so inundated with unlikely and likely |
| * conditions that the recursive nightmare that exists is too |
| * much to try to get working. At least for now. |
| */ |
| trace_likely_condition(f, val, expect); |
| |
| /* FIXME: Make this atomic! */ |
| if (val == expect) |
| f->correct++; |
| else |
| f->incorrect++; |
| } |
| EXPORT_SYMBOL(ftrace_likely_update); |
| |
| extern unsigned long __start_annotated_branch_profile[]; |
| extern unsigned long __stop_annotated_branch_profile[]; |
| |
| static int annotated_branch_stat_headers(struct seq_file *m) |
| { |
| seq_printf(m, " correct incorrect %% "); |
| seq_printf(m, " Function " |
| " File Line\n" |
| " ------- --------- - " |
| " -------- " |
| " ---- ----\n"); |
| return 0; |
| } |
| |
| static inline long get_incorrect_percent(struct ftrace_branch_data *p) |
| { |
| long percent; |
| |
| if (p->correct) { |
| percent = p->incorrect * 100; |
| percent /= p->correct + p->incorrect; |
| } else |
| percent = p->incorrect ? 100 : -1; |
| |
| return percent; |
| } |
| |
| static int branch_stat_show(struct seq_file *m, void *v) |
| { |
| struct ftrace_branch_data *p = v; |
| const char *f; |
| long percent; |
| |
| /* Only print the file, not the path */ |
| f = p->file + strlen(p->file); |
| while (f >= p->file && *f != '/') |
| f--; |
| f++; |
| |
| /* |
| * The miss is overlayed on correct, and hit on incorrect. |
| */ |
| percent = get_incorrect_percent(p); |
| |
| seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect); |
| if (percent < 0) |
| seq_printf(m, " X "); |
| else |
| seq_printf(m, "%3ld ", percent); |
| seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line); |
| return 0; |
| } |
| |
| static void *annotated_branch_stat_start(struct tracer_stat *trace) |
| { |
| return __start_annotated_branch_profile; |
| } |
| |
| static void * |
| annotated_branch_stat_next(void *v, int idx) |
| { |
| struct ftrace_branch_data *p = v; |
| |
| ++p; |
| |
| if ((void *)p >= (void *)__stop_annotated_branch_profile) |
| return NULL; |
| |
| return p; |
| } |
| |
| static int annotated_branch_stat_cmp(void *p1, void *p2) |
| { |
| struct ftrace_branch_data *a = p1; |
| struct ftrace_branch_data *b = p2; |
| |
| long percent_a, percent_b; |
| |
| percent_a = get_incorrect_percent(a); |
| percent_b = get_incorrect_percent(b); |
| |
| if (percent_a < percent_b) |
| return -1; |
| if (percent_a > percent_b) |
| return 1; |
| |
| if (a->incorrect < b->incorrect) |
| return -1; |
| if (a->incorrect > b->incorrect) |
| return 1; |
| |
| /* |
| * Since the above shows worse (incorrect) cases |
| * first, we continue that by showing best (correct) |
| * cases last. |
| */ |
| if (a->correct > b->correct) |
| return -1; |
| if (a->correct < b->correct) |
| return 1; |
| |
| return 0; |
| } |
| |
| static struct tracer_stat annotated_branch_stats = { |
| .name = "branch_annotated", |
| .stat_start = annotated_branch_stat_start, |
| .stat_next = annotated_branch_stat_next, |
| .stat_cmp = annotated_branch_stat_cmp, |
| .stat_headers = annotated_branch_stat_headers, |
| .stat_show = branch_stat_show |
| }; |
| |
| __init static int init_annotated_branch_stats(void) |
| { |
| int ret; |
| |
| ret = register_stat_tracer(&annotated_branch_stats); |
| if (!ret) { |
| printk(KERN_WARNING "Warning: could not register " |
| "annotated branches stats\n"); |
| return 1; |
| } |
| return 0; |
| } |
| fs_initcall(init_annotated_branch_stats); |
| |
| #ifdef CONFIG_PROFILE_ALL_BRANCHES |
| |
| extern unsigned long __start_branch_profile[]; |
| extern unsigned long __stop_branch_profile[]; |
| |
| static int all_branch_stat_headers(struct seq_file *m) |
| { |
| seq_printf(m, " miss hit %% "); |
| seq_printf(m, " Function " |
| " File Line\n" |
| " ------- --------- - " |
| " -------- " |
| " ---- ----\n"); |
| return 0; |
| } |
| |
| static void *all_branch_stat_start(struct tracer_stat *trace) |
| { |
| return __start_branch_profile; |
| } |
| |
| static void * |
| all_branch_stat_next(void *v, int idx) |
| { |
| struct ftrace_branch_data *p = v; |
| |
| ++p; |
| |
| if ((void *)p >= (void *)__stop_branch_profile) |
| return NULL; |
| |
| return p; |
| } |
| |
| static struct tracer_stat all_branch_stats = { |
| .name = "branch_all", |
| .stat_start = all_branch_stat_start, |
| .stat_next = all_branch_stat_next, |
| .stat_headers = all_branch_stat_headers, |
| .stat_show = branch_stat_show |
| }; |
| |
| __init static int all_annotated_branch_stats(void) |
| { |
| int ret; |
| |
| ret = register_stat_tracer(&all_branch_stats); |
| if (!ret) { |
| printk(KERN_WARNING "Warning: could not register " |
| "all branches stats\n"); |
| return 1; |
| } |
| return 0; |
| } |
| fs_initcall(all_annotated_branch_stats); |
| #endif /* CONFIG_PROFILE_ALL_BRANCHES */ |