9 files changed, 117 insertions, 43 deletions

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index bd15d7a5f5ce..e604e6ef72dd 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -181,8 +181,9 @@ struct perf_counter_attr {
                                 freq           :  1, /* use freq, not period  */
                                 inherit_stat   :  1, /* per task counts       */
                                 enable_on_exec :  1, /* next exec enables     */
+                                task           :  1, /* trace fork/exit       */
 
-                                __reserved_1   : 51;
+                                __reserved_1   : 50;
 
         __u32                   wakeup_events;  /* wakeup every n events */
         __u32                   __reserved_2;
@@ -311,6 +312,15 @@ enum perf_event_type {
         /*
          * struct {
          *      struct perf_event_header        header;
+         *      u32                             pid, ppid;
+         *      u32                             tid, ptid;
+         * };
+         */
+        PERF_EVENT_EXIT                 = 4,
+
+        /*
+         * struct {
+         *      struct perf_event_header        header;
          *      u64                             time;
          *      u64                             id;
          *      u64                             stream_id;
@@ -323,6 +333,7 @@ enum perf_event_type {
          * struct {
          *      struct perf_event_header        header;
          *      u32                             pid, ppid;
+         *      u32                             tid, ptid;
          * };
          */
         PERF_EVENT_FORK                 = 7,
diff --git a/init/Kconfig b/init/Kconfig
index cb2c09270226..3f7e60995c80 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -940,6 +940,7 @@ menu "Performance Counters"
 
 config PERF_COUNTERS
         bool "Kernel Performance Counters"
+        default y if PROFILING
         depends on HAVE_PERF_COUNTERS
         select ANON_INODES
         help
@@ -961,9 +962,17 @@ config PERF_COUNTERS
           Say Y if unsure.
 
 config EVENT_PROFILE
-        bool "Tracepoint profile sources"
+        bool "Tracepoint profiling sources"
         depends on PERF_COUNTERS && EVENT_TRACING
         default y
+        help
+         Allow the use of tracepoints as software performance counters.
+
+         When this is enabled, you can create perf counters based on
+         tracepoints using PERF_TYPE_TRACEPOINT and the tracepoint ID
+         found in debugfs://tracing/events/*/*/id. (The -e/--events
+         option to the perf tool can parse and interpret symbolic
+         tracepoints, in the subsystem:tracepoint_name format.)
 
 endmenu
 
diff --git a/kernel/fork.c b/kernel/fork.c
index 29b532e718f7..466531eb92cc 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1269,6 +1269,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         write_unlock_irq(&tasklist_lock);
         proc_fork_connector(p);
         cgroup_post_fork(p);
+        perf_counter_fork(p);
         return p;
 
 bad_fork_free_pid:
@@ -1410,9 +1411,6 @@ long do_fork(unsigned long clone_flags,
                         init_completion(&vfork);
                 }
 
-                if (!(clone_flags & CLONE_THREAD))
-                        perf_counter_fork(p);
-
                 audit_finish_fork(p);
                 tracehook_report_clone(regs, clone_flags, nr, p);
 
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 950931041954..199ed4771315 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -42,6 +42,7 @@ static int perf_overcommit __read_mostly = 1;
 static atomic_t nr_counters __read_mostly;
 static atomic_t nr_mmap_counters __read_mostly;
 static atomic_t nr_comm_counters __read_mostly;
+static atomic_t nr_task_counters __read_mostly;
 
 /*
  * perf counter paranoia level:
@@ -1654,6 +1655,8 @@ static void free_counter(struct perf_counter *counter)
                         atomic_dec(&nr_mmap_counters);
                 if (counter->attr.comm)
                         atomic_dec(&nr_comm_counters);
+                if (counter->attr.task)
+                        atomic_dec(&nr_task_counters);
         }
 
         if (counter->destroy)
@@ -1688,6 +1691,18 @@ static int perf_release(struct inode *inode, struct file *file)
         return 0;
 }
 
+static u64 perf_counter_read_tree(struct perf_counter *counter)
+{
+        struct perf_counter *child;
+        u64 total = 0;
+
+        total += perf_counter_read(counter);
+        list_for_each_entry(child, &counter->child_list, child_list)
+                total += perf_counter_read(child);
+
+        return total;
+}
+
 /*
  * Read the performance counter - simple non blocking version for now
  */
@@ -1707,7 +1722,7 @@ perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
 
         WARN_ON_ONCE(counter->ctx->parent_ctx);
         mutex_lock(&counter->child_mutex);
-        values[0] = perf_counter_read(counter);
+        values[0] = perf_counter_read_tree(counter);
         n = 1;
         if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
                 values[n++] = counter->total_time_enabled +
@@ -2819,10 +2834,12 @@ perf_counter_read_event(struct perf_counter *counter,
 }
 
 /*
- * fork tracking
+ * task tracking -- fork/exit
+ *
+ * enabled by: attr.comm | attr.mmap | attr.task
  */
 
-struct perf_fork_event {
+struct perf_task_event {
         struct task_struct      *task;
 
         struct {
@@ -2830,37 +2847,42 @@ struct perf_fork_event {
 
                 u32                             pid;
                 u32                             ppid;
+                u32                             tid;
+                u32                             ptid;
         } event;
 };
 
-static void perf_counter_fork_output(struct perf_counter *counter,
-                                     struct perf_fork_event *fork_event)
+static void perf_counter_task_output(struct perf_counter *counter,
+                                     struct perf_task_event *task_event)
 {
         struct perf_output_handle handle;
-        int size = fork_event->event.header.size;
-        struct task_struct *task = fork_event->task;
+        int size = task_event->event.header.size;
+        struct task_struct *task = task_event->task;
         int ret = perf_output_begin(&handle, counter, size, 0, 0);
 
         if (ret)
                 return;
 
-        fork_event->event.pid = perf_counter_pid(counter, task);
-        fork_event->event.ppid = perf_counter_pid(counter, task->real_parent);
+        task_event->event.pid = perf_counter_pid(counter, task);
+        task_event->event.ppid = perf_counter_pid(counter, task->real_parent);
 
-        perf_output_put(&handle, fork_event->event);
+        task_event->event.tid = perf_counter_tid(counter, task);
+        task_event->event.ptid = perf_counter_tid(counter, task->real_parent);
+
+        perf_output_put(&handle, task_event->event);
         perf_output_end(&handle);
 }
 
-static int perf_counter_fork_match(struct perf_counter *counter)
+static int perf_counter_task_match(struct perf_counter *counter)
 {
-        if (counter->attr.comm || counter->attr.mmap)
+        if (counter->attr.comm || counter->attr.mmap || counter->attr.task)
                 return 1;
 
         return 0;
 }
 
-static void perf_counter_fork_ctx(struct perf_counter_context *ctx,
-                                  struct perf_fork_event *fork_event)
+static void perf_counter_task_ctx(struct perf_counter_context *ctx,
+                                  struct perf_task_event *task_event)
 {
         struct perf_counter *counter;
 
@@ -2869,19 +2891,19 @@ static void perf_counter_fork_ctx(struct perf_counter_context *ctx,
 
         rcu_read_lock();
         list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
-                if (perf_counter_fork_match(counter))
-                        perf_counter_fork_output(counter, fork_event);
+                if (perf_counter_task_match(counter))
+                        perf_counter_task_output(counter, task_event);
         }
         rcu_read_unlock();
 }
 
-static void perf_counter_fork_event(struct perf_fork_event *fork_event)
+static void perf_counter_task_event(struct perf_task_event *task_event)
 {
         struct perf_cpu_context *cpuctx;
         struct perf_counter_context *ctx;
 
         cpuctx = &get_cpu_var(perf_cpu_context);
-        perf_counter_fork_ctx(&cpuctx->ctx, fork_event);
+        perf_counter_task_ctx(&cpuctx->ctx, task_event);
         put_cpu_var(perf_cpu_context);
 
         rcu_read_lock();
@@ -2891,32 +2913,40 @@ static void perf_counter_fork_event(struct perf_fork_event *fork_event)
          */
         ctx = rcu_dereference(current->perf_counter_ctxp);
         if (ctx)
-                perf_counter_fork_ctx(ctx, fork_event);
+                perf_counter_task_ctx(ctx, task_event);
         rcu_read_unlock();
 }
 
-void perf_counter_fork(struct task_struct *task)
+static void perf_counter_task(struct task_struct *task, int new)
 {
-        struct perf_fork_event fork_event;
+        struct perf_task_event task_event;
 
         if (!atomic_read(&nr_comm_counters) &&
-            !atomic_read(&nr_mmap_counters))
+            !atomic_read(&nr_mmap_counters) &&
+            !atomic_read(&nr_task_counters))
                 return;
 
-        fork_event = (struct perf_fork_event){
+        task_event = (struct perf_task_event){
                 .task   = task,
                 .event  = {
                         .header = {
-                                .type = PERF_EVENT_FORK,
+                                .type = new ? PERF_EVENT_FORK : PERF_EVENT_EXIT,
                                 .misc = 0,
-                                .size = sizeof(fork_event.event),
+                                .size = sizeof(task_event.event),
                         },
                         /* .pid  */
                         /* .ppid */
+                        /* .tid  */
+                        /* .ptid */
                 },
         };
 
-        perf_counter_fork_event(&fork_event);
+        perf_counter_task_event(&task_event);
+}
+
+void perf_counter_fork(struct task_struct *task)
+{
+        perf_counter_task(task, 1);
 }
 
 /*
@@ -3875,6 +3905,8 @@ done:
                         atomic_inc(&nr_mmap_counters);
                 if (counter->attr.comm)
                         atomic_inc(&nr_comm_counters);
+                if (counter->attr.task)
+                        atomic_inc(&nr_task_counters);
         }
 
         return counter;
@@ -4236,8 +4268,10 @@ void perf_counter_exit_task(struct task_struct *child)
         struct perf_counter_context *child_ctx;
         unsigned long flags;
 
-        if (likely(!child->perf_counter_ctxp))
+        if (likely(!child->perf_counter_ctxp)) {
+                perf_counter_task(child, 0);
                 return;
+        }
 
         local_irq_save(flags);
         /*
@@ -4255,15 +4289,22 @@ void perf_counter_exit_task(struct task_struct *child)
          * incremented the context's refcount before we do put_ctx below.
          */
         spin_lock(&child_ctx->lock);
-        child->perf_counter_ctxp = NULL;
         /*
          * If this context is a clone; unclone it so it can't get
          * swapped to another process while we're removing all
          * the counters from it.
          */
         unclone_ctx(child_ctx);
-        spin_unlock(&child_ctx->lock);
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&child_ctx->lock, flags);
+
+        /*
+         * Report the task dead after unscheduling the counters so that we
+         * won't get any samples after PERF_EVENT_EXIT. We can however still
+         * get a few PERF_EVENT_READ events.
+         */
+        perf_counter_task(child, 0);
+
+        child->perf_counter_ctxp = NULL;
 
         /*
          * We can recurse on the same lock type through:
diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index a5e9b876ca09..4b20fa47c3ab 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -345,7 +345,7 @@ BUILTIN_OBJS += builtin-stat.o
 BUILTIN_OBJS += builtin-top.o
 
 PERFLIBS = $(LIB_FILE)
-EXTLIBS = -lbfd
+EXTLIBS = -lbfd -liberty
 
 #
 # Platform specific tweaks
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index b20a4b6e31b7..ce4f28645e64 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -99,6 +99,7 @@ struct comm_event {
 struct fork_event {
         struct perf_event_header header;
         u32 pid, ppid;
+        u32 tid, ptid;
 };
 
 struct lost_event {
@@ -252,7 +253,7 @@ static int strcommon(const char *pathname)
 {
         int n = 0;
 
-        while (pathname[n] == cwd[n] && n < cwdlen)
+        while (n < cwdlen && pathname[n] == cwd[n])
                 ++n;
 
         return n;
@@ -1608,15 +1609,27 @@ process_comm_event(event_t *event, unsigned long offset, unsigned long head)
 }
 
 static int
-process_fork_event(event_t *event, unsigned long offset, unsigned long head)
+process_task_event(event_t *event, unsigned long offset, unsigned long head)
 {
         struct thread *thread = threads__findnew(event->fork.pid);
         struct thread *parent = threads__findnew(event->fork.ppid);
 
-        dprintf("%p [%p]: PERF_EVENT_FORK: %d:%d\n",
+        dprintf("%p [%p]: PERF_EVENT_%s: (%d:%d):(%d:%d)\n",
                 (void *)(offset + head),
                 (void *)(long)(event->header.size),
-                event->fork.pid, event->fork.ppid);
+                event->header.type == PERF_EVENT_FORK ? "FORK" : "EXIT",
+                event->fork.pid, event->fork.tid,
+                event->fork.ppid, event->fork.ptid);
+
+        /*
+         * A thread clone will have the same PID for both
+         * parent and child.
+         */
+        if (thread == parent)
+                return 0;
+
+        if (event->header.type == PERF_EVENT_EXIT)
+                return 0;
 
         if (!thread || !parent || thread__fork(thread, parent)) {
                 dprintf("problem processing PERF_EVENT_FORK, skipping event.\n");
@@ -1706,7 +1719,8 @@ process_event(event_t *event, unsigned long offset, unsigned long head)
                 return process_comm_event(event, offset, head);
 
         case PERF_EVENT_FORK:
-                return process_fork_event(event, offset, head);
+        case PERF_EVENT_EXIT:
+                return process_task_event(event, offset, head);
 
         case PERF_EVENT_LOST:
                 return process_lost_event(event, offset, head);
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index c0a423004e15..f139f1ab9333 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -285,6 +285,7 @@ static const char *skip_symbols[] = {
         "enter_idle",
         "exit_idle",
         "mwait_idle",
+        "mwait_idle_with_hints",
         "ppc64_runlatch_off",
         "pseries_dedicated_idle_sleep",
         NULL
diff --git a/tools/perf/util/quote.c b/tools/perf/util/quote.c
index c6e5dc0dc82f..2726fe40eb5d 100644
--- a/tools/perf/util/quote.c
+++ b/tools/perf/util/quote.c
@@ -318,7 +318,7 @@ char *quote_path_relative(const char *in, int len,
                 strbuf_addch(out, '"');
         if (prefix) {
                 int off = 0;
-                while (prefix[off] && off < len && prefix[off] == in[off])
+                while (off < len && prefix[off] && prefix[off] == in[off])
                         if (prefix[off] == '/') {
                                 prefix += off + 1;
                                 in += off + 1;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 28106059bf12..b4fe0579bd6b 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -565,7 +565,7 @@ static int dso__load_sym(struct dso *self, int fd, const char *name,
                 goto out_elf_end;
 
         secstrs = elf_getdata(sec_strndx, NULL);
-        if (symstrs == NULL)
+        if (secstrs == NULL)
                 goto out_elf_end;
 
         nr_syms = shdr.sh_size / shdr.sh_entsize;