perf top: Fix annotate for userspace

First, for programs and prelinked libraries, annotate code was
fooled by objdump output IPs (src->eip in the code) being
wrongly converted to absolute IPs. In such case there were no
conversion needed, but in

   src->eip = strtoull(src->line, NULL, 16);
   src->eip = map->unmap_ip(map, src->eip); // = eip + map->start - map->pgoff

we were reading absolute address from objdump (e.g. 8048604) and
then almost doubling it, because eip & map->start are
approximately close for small programs.

Needless to say, that later, in record_precise_ip() there was no
matching with real runtime IPs.

And second, like with `perf annotate` the problem with
non-prelinked *.so was that we were doing rip -> objdump address
conversion wrong.

Also, because unlike `perf annotate`, `perf top` code does
annotation based on absolute IPs for performance reasons(*), new
helper for mapping objdump addresse to IP is introduced.

(*) we get samples info in absolute IPs, and since we do lots of
    hit-testing on absolute IPs at runtime in record_precise_ip(), it's
    better to convert objdump addresses to IPs once and do no conversion
    at runtime.

I also had to fix how objdump output is parsed (with hardcoded
8/16 characters format, which was inappropriate for ET_DYN dsos
with small addresses like '4ac')

Also note, that not all objdump output lines has associtated
IPs, e.g. look at source lines here:

    000004ac <my_strlen>:
    extern "C"
    int my_strlen(const char *s)
     4ac:   55                      push   %ebp
     4ad:   89 e5                   mov    %esp,%ebp
     4af:   83 ec 10                sub    $0x10,%esp
    {
        int len = 0;
     4b2:   c7 45 fc 00 00 00 00    movl   $0x0,-0x4(%ebp)
     4b9:   eb 08                   jmp    4c3 <my_strlen+0x17>

        while (*s) {
            ++len;
     4bb:   83 45 fc 01             addl   $0x1,-0x4(%ebp)
            ++s;
     4bf:   83 45 08 01             addl   $0x1,0x8(%ebp)

So we mark them with eip=0, and ignore such lines in annotate
lookup code.

Signed-off-by: Kirill Smelkov <kirr@landau.phys.spbu.ru>
[ Note: one hunk of this patch was applied by Mike in 57d8188 ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1265550376-12665-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index e4156bc..befa57e 100644 (file)
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -216,7 +216,7 @@ static void parse_source(struct sym_entry *syme)
        while (!feof(file)) {
                struct source_line *src;
                size_t dummy = 0;
-               char *c;
+               char *c, *sep;
 
                src = malloc(sizeof(struct source_line));
                assert(src != NULL);
@@ -235,14 +235,11 @@ static void parse_source(struct sym_entry *syme)
                *source->lines_tail = src;
                source->lines_tail = &src->next;
 
-               if (strlen(src->line)>8 && src->line[8] == ':') {
-                       src->eip = strtoull(src->line, NULL, 16);
-                       src->eip = map->unmap_ip(map, src->eip);
-               }
-               if (strlen(src->line)>8 && src->line[16] == ':') {
-                       src->eip = strtoull(src->line, NULL, 16);
-                       src->eip = map->unmap_ip(map, src->eip);
-               }
+               src->eip = strtoull(src->line, &sep, 16);
+               if (*sep == ':')
+                       src->eip = map__objdump_2ip(map, src->eip);
+               else /* this line has no ip info (e.g. source line) */
+                       src->eip = 0;
        }
        pclose(file);
 out_assign:
@@ -277,6 +274,9 @@ static void record_precise_ip(struct sym_entry *syme, int counter, u64 ip)
                goto out_unlock;
 
        for (line = syme->src->lines; line; line = line->next) {
+               /* skip lines without IP info */
+               if (line->eip == 0)
+                       continue;
                if (line->eip == ip) {
                        line->count[counter]++;
                        break;

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index af5805f..138e3cb 100644 (file)
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -222,3 +222,11 @@ u64 map__rip_2objdump(struct map *map, u64 rip)
                        rip;
        return addr;
 }
+
+u64 map__objdump_2ip(struct map *map, u64 addr)
+{
+       u64 ip = map->dso->adjust_symbols ?
+                       addr :
+                       map->unmap_ip(map, addr);       /* RIP -> IP */
+       return ip;
+}

diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 9cee9c7..86f77cb 100644 (file)
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -61,9 +61,9 @@ static inline u64 identity__map_ip(struct map *map __used, u64 ip)
 }
 
 
-/* rip -> addr suitable for passing to `objdump --start-address=` */
+/* rip/ip <-> addr suitable for passing to `objdump --start-address=` */
 u64 map__rip_2objdump(struct map *map, u64 rip);
-
+u64 map__objdump_2ip(struct map *map, u64 addr);
 
 struct symbol;
 struct mmap_event;