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SubjectRe: [PATCH] perf script: Show binary offsets for userspace addr
Em Wed, Oct 20, 2021 at 03:24:19PM +0200, Jiri Olsa escreveu:
> On Tue, Oct 19, 2021 at 03:24:17PM +0800, Lexi Shao wrote:
> > Show binary offsets for userspace addr with map in perf script output
> > with callchain.
> >
> > In commit 19610184693c("perf script: Show virtual addresses instead of
> > offsets"), the addr shown in perf script output with callchain is changed
> > from binary offsets to virtual address to fix the incorrectness when
> > displaying symbol offset.
> >
> > This is inconvenient in scenario that the binary is stripped and
> > symbol cannot be resolved. If someone wants to further resolve symbols for
> > specific binaries later, he would need an extra step to translate virtual
> > address to binary offset with mapping information recorded in perf.data,
> > which can be difficult for people not familiar with perf.
> >
> > This patch modifies function sample__fprintf_callchain to print binary
> > offset for userspace addr with dsos, and virtual address otherwise. It
> > does not affect symbol offset calculation so symoff remains correct.
> >
> > Before applying this patch:
> > test 1512 78.711307: 533129 cycles:
> > aaaae0da07f4 [unknown] (/tmp/test)
> > aaaae0da0704 [unknown] (/tmp/test)
> > ffffbe9f7ef4 __libc_start_main+0xe4 (/lib64/libc-2.31.so)
> >
> > After this patch:
> > test 1519 111.330127: 406953 cycles:
> > 7f4 [unknown] (/tmp/test)
> > 704 [unknown] (/tmp/test)
> > 20ef4 __libc_start_main+0xe4 (/lib64/libc-2.31.so)
> >
> > Fixes: 19610184693c("perf script: Show virtual addresses instead of offsets")
> >
> > Signed-off-by: Lexi Shao <shaolexi@huawei.com>
>
> makes sense to me
>
> Acked-/Tested-by Jiri Olsa <jolsa@redhat.com>

Thanks, applied.

- Arnaldo


> should we have a way to display these callchain detail in perf report output as well?
>
> thanks,
> jirka
>
> > ---
> > tools/perf/util/evsel_fprintf.c | 12 +++++++++---
> > 1 file changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/util/evsel_fprintf.c b/tools/perf/util/evsel_fprintf.c
> > index bfedd7b23521..8c2ea8001329 100644
> > --- a/tools/perf/util/evsel_fprintf.c
> > +++ b/tools/perf/util/evsel_fprintf.c
> > @@ -11,6 +11,7 @@
> > #include "strlist.h"
> > #include "symbol.h"
> > #include "srcline.h"
> > +#include "dso.h"
> >
> > static int comma_fprintf(FILE *fp, bool *first, const char *fmt, ...)
> > {
> > @@ -144,12 +145,17 @@ int sample__fprintf_callchain(struct perf_sample *sample, int left_alignment,
> > if (print_arrow && !first)
> > printed += fprintf(fp, " <-");
> >
> > - if (print_ip)
> > - printed += fprintf(fp, "%c%16" PRIx64, s, node->ip);
> > -
> > if (map)
> > addr = map->map_ip(map, node->ip);
> >
> > + if (print_ip) {
> > + /* Show binary offset for userspace addr */
> > + if (map && !map->dso->kernel)
> > + printed += fprintf(fp, "%c%16" PRIx64, s, addr);
> > + else
> > + printed += fprintf(fp, "%c%16" PRIx64, s, node->ip);
> > + }
> > +
> > if (print_sym) {
> > printed += fprintf(fp, " ");
> > node_al.addr = addr;
> > --
> > 2.12.3
> >

--

- Arnaldo

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