3 files changed, 78 insertions, 56 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index fc3709cba136..f0467ff0d8ad 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -574,11 +574,11 @@ static int __cmd_record(int argc, const char **argv)
                 header = perf_header__new();
 
         if (raw_samples) {
-                perf_header__set_trace_info();
+                perf_header__feat_trace_info(header);
         } else {
                 for (i = 0; i < nr_counters; i++) {
                         if (attrs[i].sample_type & PERF_SAMPLE_RAW) {
-                                perf_header__set_trace_info();
+                                perf_header__feat_trace_info(header);
                                 break;
                         }
                 }
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 9aae360c0f28..171d51b6f359 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -8,6 +8,8 @@
 #include "../perf.h"
 #include "trace-event.h"
 
+#include <linux/bitmap.h>
+
 /*
  * Create new perf.data header attribute:
  */
@@ -48,25 +50,17 @@ void perf_header_attr__add_id(struct perf_header_attr *self, u64 id)
  */
 struct perf_header *perf_header__new(void)
 {
-        struct perf_header *self = malloc(sizeof(*self));
+        struct perf_header *self = calloc(sizeof(*self), 1);
 
         if (!self)
                 die("nomem");
 
-        self->frozen = 0;
-
-        self->attrs = 0;
         self->size = 1;
         self->attr = malloc(sizeof(void *));
 
         if (!self->attr)
                 die("nomem");
 
-        self->data_offset = 0;
-        self->data_size = 0;
-        self->trace_info_offset = 0;
-        self->trace_info_size = 0;
-
         return self;
 }
 
@@ -149,14 +143,12 @@ struct perf_file_header {
         struct perf_file_section        attrs;
         struct perf_file_section        data;
         struct perf_file_section        event_types;
-        struct perf_file_section        trace_info;
+        feat_mask_t                     adds_features;
 };
 
-static int trace_info;
-
-void perf_header__set_trace_info(void)
+void perf_header__feat_trace_info(struct perf_header *header)
 {
-        trace_info = 1;
+        set_bit(HEADER_TRACE_INFO, perf_header__adds_mask(header));
 }
 
 static void do_write(int fd, void *buf, size_t size)
@@ -172,6 +164,32 @@ static void do_write(int fd, void *buf, size_t size)
         }
 }
 
+static void perf_header__adds_write(struct perf_header *self, int fd)
+{
+        struct perf_file_section trace_sec;
+        u64 cur_offset = lseek(fd, 0, SEEK_CUR);
+        unsigned long *feat_mask = perf_header__adds_mask(self);
+
+        if (test_bit(HEADER_TRACE_INFO, feat_mask)) {
+                /* Write trace info */
+                trace_sec.offset = lseek(fd, sizeof(trace_sec), SEEK_CUR);
+                read_tracing_data(fd, attrs, nr_counters);
+                trace_sec.size = lseek(fd, 0, SEEK_CUR) - trace_sec.offset;
+
+                /* Write trace info headers */
+                lseek(fd, cur_offset, SEEK_SET);
+                do_write(fd, &trace_sec, sizeof(trace_sec));
+
+                /*
+                 * Update cur_offset. So that other (future)
+                 * features can set their own infos in this place. But if we are
+                 * the only feature, at least that seeks to the place the data
+                 * should begin.
+                 */
+                cur_offset = lseek(fd, trace_sec.offset + trace_sec.size, SEEK_SET);
+        }
+};
+
 void perf_header__write(struct perf_header *self, int fd)
 {
         struct perf_file_header f_header;
@@ -210,23 +228,7 @@ void perf_header__write(struct perf_header *self, int fd)
         if (events)
                 do_write(fd, events, self->event_size);
 
-        if (trace_info) {
-                static int trace_info_written;
-
-                /*
-                 * Write it only once
-                 */
-                if (!trace_info_written) {
-                        self->trace_info_offset = lseek(fd, 0, SEEK_CUR);
-                        read_tracing_data(fd, attrs, nr_counters);
-                        self->trace_info_size = lseek(fd, 0, SEEK_CUR) -
-                                                self->trace_info_offset;
-                        trace_info_written = 1;
-                } else {
-                        lseek(fd, self->trace_info_offset +
-                                self->trace_info_size, SEEK_SET);
-                }
-        }
+        perf_header__adds_write(self, fd);
 
         self->data_offset = lseek(fd, 0, SEEK_CUR);
 
@@ -246,12 +248,10 @@ void perf_header__write(struct perf_header *self, int fd)
                         .offset = self->event_offset,
                         .size   = self->event_size,
                 },
-                .trace_info = {
-                        .offset = self->trace_info_offset,
-                        .size = self->trace_info_size,
-                },
         };
 
+        memcpy(&f_header.adds_features, &self->adds_features, sizeof(feat_mask_t));
+
         lseek(fd, 0, SEEK_SET);
         do_write(fd, &f_header, sizeof(f_header));
         lseek(fd, self->data_offset + self->data_size, SEEK_SET);
@@ -274,6 +274,20 @@ static void do_read(int fd, void *buf, size_t size)
         }
 }
 
+static void perf_header__adds_read(struct perf_header *self, int fd)
+{
+        const unsigned long *feat_mask = perf_header__adds_mask(self);
+
+        if (test_bit(HEADER_TRACE_INFO, feat_mask)) {
+                struct perf_file_section trace_sec;
+
+                do_read(fd, &trace_sec, sizeof(trace_sec));
+                lseek(fd, trace_sec.offset, SEEK_SET);
+                trace_report(fd);
+                lseek(fd, trace_sec.offset + trace_sec.size, SEEK_SET);
+        }
+};
+
 struct perf_header *perf_header__read(int fd)
 {
         struct perf_header      *self = perf_header__new();
@@ -292,9 +306,11 @@ struct perf_header *perf_header__read(int fd)
 
         if (f_header.size != sizeof(f_header)) {
                 /* Support the previous format */
-                if (f_header.size == offsetof(typeof(f_header), trace_info))
-                        f_header.trace_info.size = 0;
-                else
+                if (f_header.size == offsetof(typeof(f_header), adds_features)) {
+                        unsigned long *mask = (unsigned long *)(void *)
+                                        &f_header.adds_features;
+                        bitmap_zero(mask, HEADER_FEAT_BITS);
+                } else
                         die("incompatible file format");
         }
         nr_attrs = f_header.attrs.size / sizeof(f_attr);
@@ -330,13 +346,9 @@ struct perf_header *perf_header__read(int fd)
                 event_count =  f_header.event_types.size / sizeof(struct perf_trace_event_type);
         }
 
-        self->trace_info_offset = f_header.trace_info.offset;
-        self->trace_info_size = f_header.trace_info.size;
+        memcpy(&self->adds_features, &f_header.adds_features, sizeof(feat_mask_t));
 
-        if (self->trace_info_size) {
-                lseek(fd, self->trace_info_offset, SEEK_SET);
-                trace_report(fd);
-        }
+        perf_header__adds_read(self, fd);
 
         self->event_offset = f_header.event_types.offset;
         self->event_size   = f_header.event_types.size;
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 30aee5160dc0..0eb4a9126b7c 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -12,19 +12,29 @@ struct perf_header_attr {
         off_t id_offset;
 };
 
+#define HEADER_TRACE_INFO                       1
+
+#define HEADER_FEAT_BITS                        256
+
+typedef typeof(u64[HEADER_FEAT_BITS / 8])       feat_mask_t;
+
 struct perf_header {
-        int frozen;
-        int attrs, size;
+        int                     frozen;
+        int                     attrs, size;
         struct perf_header_attr **attr;
-        s64 attr_offset;
-        u64 data_offset;
-        u64 data_size;
-        u64 event_offset;
-        u64 event_size;
-        u64 trace_info_offset;
-        u64 trace_info_size;
+        s64                     attr_offset;
+        u64                     data_offset;
+        u64                     data_size;
+        u64                     event_offset;
+        u64                     event_size;
+        feat_mask_t             adds_features;
 };
 
+static inline unsigned long *perf_header__adds_mask(struct perf_header *self)
+{
+        return (unsigned long *)(void *)&self->adds_features;
+}
+
 struct perf_header *perf_header__read(int fd);
 void perf_header__write(struct perf_header *self, int fd);
 
@@ -42,7 +52,7 @@ void perf_header_attr__add_id(struct perf_header_attr *self, u64 id);
 u64 perf_header__sample_type(struct perf_header *header);
 struct perf_event_attr *
 perf_header__find_attr(u64 id, struct perf_header *header);
-void perf_header__set_trace_info(void);
+void perf_header__feat_trace_info(struct perf_header *header);
 
 struct perf_header *perf_header__new(void);