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>

1 files changed, 52 insertions, 42 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)