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>
This commit is contained in:
parent
5ecaafdbf4
commit
ee11b90b12
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@ -216,7 +216,7 @@ static void parse_source(struct sym_entry *syme)
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while (!feof(file)) {
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struct source_line *src;
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size_t dummy = 0;
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char *c;
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char *c, *sep;
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src = malloc(sizeof(struct source_line));
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assert(src != NULL);
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@ -235,14 +235,11 @@ static void parse_source(struct sym_entry *syme)
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*source->lines_tail = src;
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source->lines_tail = &src->next;
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if (strlen(src->line)>8 && src->line[8] == ':') {
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src->eip = strtoull(src->line, NULL, 16);
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src->eip = map->unmap_ip(map, src->eip);
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}
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if (strlen(src->line)>8 && src->line[16] == ':') {
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src->eip = strtoull(src->line, NULL, 16);
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src->eip = map->unmap_ip(map, src->eip);
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}
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src->eip = strtoull(src->line, &sep, 16);
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if (*sep == ':')
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src->eip = map__objdump_2ip(map, src->eip);
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else /* this line has no ip info (e.g. source line) */
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src->eip = 0;
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}
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pclose(file);
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out_assign:
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@ -277,6 +274,9 @@ static void record_precise_ip(struct sym_entry *syme, int counter, u64 ip)
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goto out_unlock;
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for (line = syme->src->lines; line; line = line->next) {
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/* skip lines without IP info */
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if (line->eip == 0)
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continue;
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if (line->eip == ip) {
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line->count[counter]++;
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break;
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@ -222,3 +222,11 @@ u64 map__rip_2objdump(struct map *map, u64 rip)
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rip;
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return addr;
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}
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u64 map__objdump_2ip(struct map *map, u64 addr)
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{
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u64 ip = map->dso->adjust_symbols ?
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addr :
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map->unmap_ip(map, addr); /* RIP -> IP */
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return ip;
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}
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@ -61,9 +61,9 @@ static inline u64 identity__map_ip(struct map *map __used, u64 ip)
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}
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/* rip -> addr suitable for passing to `objdump --start-address=` */
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/* rip/ip <-> addr suitable for passing to `objdump --start-address=` */
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u64 map__rip_2objdump(struct map *map, u64 rip);
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u64 map__objdump_2ip(struct map *map, u64 addr);
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struct symbol;
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struct mmap_event;
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