litmus-rt.git - The LITMUS^RT kernel.

diff options

author	Jiri Olsa <jolsa@kernel.org>	2014-12-10 15:23:51 -0500
committer	Ingo Molnar <mingo@kernel.org>	2014-12-11 05:24:15 -0500
commit	9fc81d87420d0d3fd62d5e5529972c0ad9eab9cc (patch)
tree	6958852fa791c6aed73eff5def1287c2a5b3fb52 /tools/perf/scripts/python/sched-migration.py
parent	af91568e762d04931dcbdd6bef4655433d8b9418 (diff)

perf: Fix events installation during moving group

We allow PMU driver to change the cpu on which the event should be installed to. This happened in patch: e2d37cd213dc ("perf: Allow the PMU driver to choose the CPU on which to install events") This patch also forces all the group members to follow the currently opened events cpu if the group happened to be moved. This and the change of event->cpu in perf_install_in_context() function introduced in: 0cda4c023132 ("perf: Introduce perf_pmu_migrate_context()") forces group members to change their event->cpu, if the currently-opened-event's PMU changed the cpu and there is a group move. Above behaviour causes problem for breakpoint events, which uses event->cpu to touch cpu specific data for breakpoints accounting. By changing event->cpu, some breakpoints slots were wrongly accounted for given cpu. Vinces's perf fuzzer hit this issue and caused following WARN on my setup: WARNING: CPU: 0 PID: 20214 at arch/x86/kernel/hw_breakpoint.c:119 arch_install_hw_breakpoint+0x142/0x150() Can't find any breakpoint slot [...] This patch changes the group moving code to keep the event's original cpu. Reported-by: Vince Weaver <vince@deater.net> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vince@deater.net> Cc: Yan, Zheng <zheng.z.yan@intel.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1418243031-20367-3-git-send-email-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>

Diffstat (limited to 'tools/perf/scripts/python/sched-migration.py')

0 files changed, 0 insertions, 0 deletions

/* * 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,


context:
space:
mode: