perf_counter tools: Add a data file header

Add a data file header so we can transfer data between record and report.

LKML-Reference: <new-submission>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 73 insertions, 43 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 06fdfb8b4828..28304677c73e 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -51,6 +51,9 @@ static struct pollfd		event_array[MAX_NR_CPUS * MAX_COUNTERS];
 static int                      nr_poll;
 static int                      nr_cpu;
 
+static int                      file_new = 1;
+static struct perf_file_header  file_header;
+
 struct mmap_event {
         struct perf_event_header        header;
         __u32                           pid;
@@ -100,6 +103,21 @@ static void mmap_write_tail(struct mmap_data *md, unsigned long tail)
         pc->data_tail = tail;
 }
 
+static void write_output(void *buf, size_t size)
+{
+        while (size) {
+                int ret = write(output, buf, size);
+
+                if (ret < 0)
+                        die("failed to write");
+
+                size -= ret;
+                buf += ret;
+
+                bytes_written += ret;
+        }
+}
+
 static void mmap_read(struct mmap_data *md)
 {
         unsigned int head = mmap_read_head(md);
@@ -148,34 +166,14 @@ static void mmap_read(struct mmap_data *md)
                 size = md->mask + 1 - (old & md->mask);
                 old += size;
 
-                while (size) {
-                        int ret = write(output, buf, size);
-
-                        if (ret < 0)
-                                die("failed to write");
-
-                        size -= ret;
-                        buf += ret;
-
-                        bytes_written += ret;
-                }
+                write_output(buf, size);
         }
 
         buf = &data[old & md->mask];
         size = head - old;
         old += size;
 
-        while (size) {
-                int ret = write(output, buf, size);
-
-                if (ret < 0)
-                        die("failed to write");
-
-                size -= ret;
-                buf += ret;
-
-                bytes_written += ret;
-        }
+        write_output(buf, size);
 
         md->prev = old;
         mmap_write_tail(md, old);
@@ -204,7 +202,7 @@ static void pid_synthesize_comm_event(pid_t pid, int full)
         struct comm_event comm_ev;
         char filename[PATH_MAX];
         char bf[BUFSIZ];
-        int fd, ret;
+        int fd;
         size_t size;
         char *field, *sep;
         DIR *tasks;
@@ -246,11 +244,7 @@ static void pid_synthesize_comm_event(pid_t pid, int full)
         if (!full) {
                 comm_ev.tid = pid;
 
-                ret = write(output, &comm_ev, comm_ev.header.size);
-                if (ret < 0) {
-                        perror("failed to write");
-                        exit(-1);
-                }
+                write_output(&comm_ev, comm_ev.header.size);
                 return;
         }
 
@@ -265,11 +259,7 @@ static void pid_synthesize_comm_event(pid_t pid, int full)
 
                 comm_ev.tid = pid;
 
-                ret = write(output, &comm_ev, comm_ev.header.size);
-                if (ret < 0) {
-                        perror("failed to write");
-                        exit(-1);
-                }
+                write_output(&comm_ev, comm_ev.header.size);
         }
         closedir(tasks);
         return;
@@ -332,10 +322,7 @@ static void pid_synthesize_mmap_samples(pid_t pid)
                         mmap_ev.pid = pid;
                         mmap_ev.tid = pid;
 
-                        if (write(output, &mmap_ev, mmap_ev.header.size) < 0) {
-                                perror("failed to write");
-                                exit(-1);
-                        }
+                        write_output(&mmap_ev, mmap_ev.header.size);
                 }
         }
 
@@ -382,6 +369,15 @@ static void create_counter(int counter, int cpu, pid_t pid)
         if (call_graph)
                 attr->sample_type       |= PERF_SAMPLE_CALLCHAIN;
 
+        if (file_new) {
+                file_header.sample_type = attr->sample_type;
+        } else {
+                if (file_header.sample_type != attr->sample_type) {
+                        fprintf(stderr, "incompatible append\n");
+                        exit(-1);
+                }
+        }
+
         attr->mmap              = track;
         attr->comm              = track;
         attr->inherit           = (cpu < 0) && inherit;
@@ -461,6 +457,13 @@ static void open_counters(int cpu, pid_t pid)
         nr_cpu++;
 }
 
+static void atexit_header(void)
+{
+        file_header.data_size += bytes_written;
+
+        pwrite(output, &file_header, sizeof(file_header), 0);
+}
+
 static int __cmd_record(int argc, const char **argv)
 {
         int i, counter;
@@ -474,6 +477,10 @@ static int __cmd_record(int argc, const char **argv)
         assert(nr_cpus <= MAX_NR_CPUS);
         assert(nr_cpus >= 0);
 
+        atexit(sig_atexit);
+        signal(SIGCHLD, sig_handler);
+        signal(SIGINT, sig_handler);
+
         if (!stat(output_name, &st) && !force && !append_file) {
                 fprintf(stderr, "Error, output file %s exists, use -A to append or -f to overwrite.\n",
                                 output_name);
@@ -482,7 +489,7 @@ static int __cmd_record(int argc, const char **argv)
 
         flags = O_CREAT|O_RDWR;
         if (append_file)
-                flags |= O_APPEND;
+                file_new = 0;
         else
                 flags |= O_TRUNC;
 
@@ -492,15 +499,18 @@ static int __cmd_record(int argc, const char **argv)
                 exit(-1);
         }
 
+        if (!file_new) {
+                read(output, &file_header, sizeof(file_header));
+                lseek(output, file_header.data_size, SEEK_CUR);
+        }
+
+        atexit(atexit_header);
+
         if (!system_wide) {
                 open_counters(-1, target_pid != -1 ? target_pid : getpid());
         } else for (i = 0; i < nr_cpus; i++)
                 open_counters(i, target_pid);
 
-        atexit(sig_atexit);
-        signal(SIGCHLD, sig_handler);
-        signal(SIGINT, sig_handler);
-
         if (target_pid == -1 && argc) {
                 pid = fork();
                 if (pid < 0)
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 7a6577bf9a41..37b26ecb0d0b 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -1366,11 +1366,13 @@ process_event(event_t *event, unsigned long offset, unsigned long head)
         return 0;
 }
 
+static struct perf_file_header          file_header;
+
 static int __cmd_report(void)
 {
         int ret, rc = EXIT_FAILURE;
         unsigned long offset = 0;
-        unsigned long head = 0;
+        unsigned long head = sizeof(file_header);
         struct stat stat;
         event_t *event;
         uint32_t size;
@@ -1398,6 +1400,14 @@ static int __cmd_report(void)
                 exit(0);
         }
 
+        read(input, &file_header, sizeof(file_header));
+
+        if (sort__has_parent &&
+            !(file_header.sample_type & PERF_SAMPLE_CALLCHAIN)) {
+                fprintf(stderr, "selected --sort parent, but no callchain data\n");
+                exit(-1);
+        }
+
         if (load_kernel() < 0) {
                 perror("failed to load kernel symbols");
                 return EXIT_FAILURE;
@@ -1469,9 +1479,13 @@ more:
 
         head += size;
 
+        if (offset + head >= sizeof(file_header) + file_header.data_size)
+                goto done;
+
         if (offset + head < stat.st_size)
                 goto more;
 
+done:
         rc = EXIT_SUCCESS;
         close(input);
 
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 87a1aca4a424..55c62f4b990b 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -65,4 +65,10 @@ sys_perf_counter_open(struct perf_counter_attr *attr,
 #define MAX_COUNTERS                    256
 #define MAX_NR_CPUS                     256
 
+struct perf_file_header {
+        __u64   version;
+        __u64   sample_type;
+        __u64   data_size;
+};
+
 #endif