perf tools: Add a thread stack for synthesizing call chains

Add a thread stack for synthesizing call chains from call and return
events.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1414678188-14946-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

6 files changed, 238 insertions, 0 deletions

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 3caf7dab50e8..0ebcc4ad0244 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -317,6 +317,7 @@ LIB_H += ui/util.h
 LIB_H += ui/ui.h
 LIB_H += util/data.h
 LIB_H += util/kvm-stat.h
+LIB_H += util/thread-stack.h
 
 LIB_OBJS += $(OUTPUT)util/abspath.o
 LIB_OBJS += $(OUTPUT)util/alias.o
@@ -394,6 +395,7 @@ LIB_OBJS += $(OUTPUT)util/srcline.o
 LIB_OBJS += $(OUTPUT)util/data.o
 LIB_OBJS += $(OUTPUT)util/tsc.o
 LIB_OBJS += $(OUTPUT)util/cloexec.o
+LIB_OBJS += $(OUTPUT)util/thread-stack.o
 
 LIB_OBJS += $(OUTPUT)ui/setup.o
 LIB_OBJS += $(OUTPUT)ui/helpline.o
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 8c7fe9d64e79..7be389735402 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -143,6 +143,32 @@ struct branch_stack {
         struct branch_entry     entries[0];
 };
 
+enum {
+        PERF_IP_FLAG_BRANCH             = 1ULL << 0,
+        PERF_IP_FLAG_CALL               = 1ULL << 1,
+        PERF_IP_FLAG_RETURN             = 1ULL << 2,
+        PERF_IP_FLAG_CONDITIONAL        = 1ULL << 3,
+        PERF_IP_FLAG_SYSCALLRET         = 1ULL << 4,
+        PERF_IP_FLAG_ASYNC              = 1ULL << 5,
+        PERF_IP_FLAG_INTERRUPT          = 1ULL << 6,
+        PERF_IP_FLAG_TX_ABORT           = 1ULL << 7,
+        PERF_IP_FLAG_TRACE_BEGIN        = 1ULL << 8,
+        PERF_IP_FLAG_TRACE_END          = 1ULL << 9,
+        PERF_IP_FLAG_IN_TX              = 1ULL << 10,
+};
+
+#define PERF_BRANCH_MASK                (\
+        PERF_IP_FLAG_BRANCH             |\
+        PERF_IP_FLAG_CALL               |\
+        PERF_IP_FLAG_RETURN             |\
+        PERF_IP_FLAG_CONDITIONAL        |\
+        PERF_IP_FLAG_SYSCALLRET         |\
+        PERF_IP_FLAG_ASYNC              |\
+        PERF_IP_FLAG_INTERRUPT          |\
+        PERF_IP_FLAG_TX_ABORT           |\
+        PERF_IP_FLAG_TRACE_BEGIN        |\
+        PERF_IP_FLAG_TRACE_END)
+
 struct perf_sample {
         u64 ip;
         u32 pid, tid;
diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c
new file mode 100644
index 000000000000..85b60d2e738f
--- /dev/null
+++ b/tools/perf/util/thread-stack.c
@@ -0,0 +1,172 @@
+/*
+ * thread-stack.c: Synthesize a thread's stack using call / return events
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include "thread.h"
+#include "event.h"
+#include "util.h"
+#include "debug.h"
+#include "thread-stack.h"
+
+#define STACK_GROWTH 4096
+
+struct thread_stack_entry {
+        u64 ret_addr;
+};
+
+struct thread_stack {
+        struct thread_stack_entry *stack;
+        size_t cnt;
+        size_t sz;
+        u64 trace_nr;
+};
+
+static int thread_stack__grow(struct thread_stack *ts)
+{
+        struct thread_stack_entry *new_stack;
+        size_t sz, new_sz;
+
+        new_sz = ts->sz + STACK_GROWTH;
+        sz = new_sz * sizeof(struct thread_stack_entry);
+
+        new_stack = realloc(ts->stack, sz);
+        if (!new_stack)
+                return -ENOMEM;
+
+        ts->stack = new_stack;
+        ts->sz = new_sz;
+
+        return 0;
+}
+
+static struct thread_stack *thread_stack__new(void)
+{
+        struct thread_stack *ts;
+
+        ts = zalloc(sizeof(struct thread_stack));
+        if (!ts)
+                return NULL;
+
+        if (thread_stack__grow(ts)) {
+                free(ts);
+                return NULL;
+        }
+
+        return ts;
+}
+
+static int thread_stack__push(struct thread_stack *ts, u64 ret_addr)
+{
+        int err = 0;
+
+        if (ts->cnt == ts->sz) {
+                err = thread_stack__grow(ts);
+                if (err) {
+                        pr_warning("Out of memory: discarding thread stack\n");
+                        ts->cnt = 0;
+                }
+        }
+
+        ts->stack[ts->cnt++].ret_addr = ret_addr;
+
+        return err;
+}
+
+static void thread_stack__pop(struct thread_stack *ts, u64 ret_addr)
+{
+        size_t i;
+
+        /*
+         * In some cases there may be functions which are not seen to return.
+         * For example when setjmp / longjmp has been used.  Or the perf context
+         * switch in the kernel which doesn't stop and start tracing in exactly
+         * the same code path.  When that happens the return address will be
+         * further down the stack.  If the return address is not found at all,
+         * we assume the opposite (i.e. this is a return for a call that wasn't
+         * seen for some reason) and leave the stack alone.
+         */
+        for (i = ts->cnt; i; ) {
+                if (ts->stack[--i].ret_addr == ret_addr) {
+                        ts->cnt = i;
+                        return;
+                }
+        }
+}
+
+int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip,
+                        u64 to_ip, u16 insn_len, u64 trace_nr)
+{
+        if (!thread)
+                return -EINVAL;
+
+        if (!thread->ts) {
+                thread->ts = thread_stack__new();
+                if (!thread->ts) {
+                        pr_warning("Out of memory: no thread stack\n");
+                        return -ENOMEM;
+                }
+                thread->ts->trace_nr = trace_nr;
+        }
+
+        /*
+         * When the trace is discontinuous, the trace_nr changes.  In that case
+         * the stack might be completely invalid.  Better to report nothing than
+         * to report something misleading, so reset the stack count to zero.
+         */
+        if (trace_nr != thread->ts->trace_nr) {
+                thread->ts->trace_nr = trace_nr;
+                thread->ts->cnt = 0;
+        }
+
+        if (flags & PERF_IP_FLAG_CALL) {
+                u64 ret_addr;
+
+                if (!to_ip)
+                        return 0;
+                ret_addr = from_ip + insn_len;
+                if (ret_addr == to_ip)
+                        return 0; /* Zero-length calls are excluded */
+                return thread_stack__push(thread->ts, ret_addr);
+        } else if (flags & PERF_IP_FLAG_RETURN) {
+                if (!from_ip)
+                        return 0;
+                thread_stack__pop(thread->ts, to_ip);
+        }
+
+        return 0;
+}
+
+void thread_stack__free(struct thread *thread)
+{
+        if (thread->ts) {
+                zfree(&thread->ts->stack);
+                zfree(&thread->ts);
+        }
+}
+
+void thread_stack__sample(struct thread *thread, struct ip_callchain *chain,
+                          size_t sz, u64 ip)
+{
+        size_t i;
+
+        if (!thread || !thread->ts)
+                chain->nr = 1;
+        else
+                chain->nr = min(sz, thread->ts->cnt + 1);
+
+        chain->ips[0] = ip;
+
+        for (i = 1; i < chain->nr; i++)
+                chain->ips[i] = thread->ts->stack[thread->ts->cnt - i].ret_addr;
+}
diff --git a/tools/perf/util/thread-stack.h b/tools/perf/util/thread-stack.h
new file mode 100644
index 000000000000..7c41579aec74
--- /dev/null
+++ b/tools/perf/util/thread-stack.h
@@ -0,0 +1,32 @@
+/*
+ * thread-stack.h: Synthesize a thread's stack using call / return events
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifndef __PERF_THREAD_STACK_H
+#define __PERF_THREAD_STACK_H
+
+#include <sys/types.h>
+
+#include <linux/types.h>
+
+struct thread;
+struct ip_callchain;
+
+int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip,
+                        u64 to_ip, u16 insn_len, u64 trace_nr);
+void thread_stack__sample(struct thread *thread, struct ip_callchain *chain,
+                          size_t sz, u64 ip);
+void thread_stack__free(struct thread *thread);
+
+#endif
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index bf5bf858b7f6..a2157f0ef1df 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -4,6 +4,7 @@
 #include <string.h>
 #include "session.h"
 #include "thread.h"
+#include "thread-stack.h"
 #include "util.h"
 #include "debug.h"
 #include "comm.h"
@@ -66,6 +67,8 @@ void thread__delete(struct thread *thread)
 {
         struct comm *comm, *tmp;
 
+        thread_stack__free(thread);
+
         if (thread->mg) {
                 map_groups__put(thread->mg);
                 thread->mg = NULL;
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index d34cf5c0d0d9..160fd066a7d1 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -8,6 +8,8 @@
 #include "symbol.h"
 #include <strlist.h>
 
+struct thread_stack;
+
 struct thread {
         union {
                 struct rb_node   rb_node;
@@ -26,6 +28,7 @@ struct thread {
         u64                     db_id;
 
         void                    *priv;
+        struct thread_stack     *ts;
 };
 
 struct machine;