From: David Ahern Date: Fri, 20 Jul 2012 23:25:49 +0000 (-0600) Subject: perf kvm: Fix bug resolving guest kernel syms X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=adb5d2a487c55e5ca2ecc0b73c8f592e95d292c7;p=openwrt%2Fstaging%2Fblogic.git perf kvm: Fix bug resolving guest kernel syms Guest kernel symbols are not resolved despite passing the information needed to resolve them. e.g., perf kvm --guest --guestmount=/tmp/guest-mount record -a -- sleep 1 perf kvm --guest --guestmount=/tmp/guest-mount report --stdio 36.55% [guest/11399] [unknown] [g] 0xffffffff81600bc8 33.19% [guest/10474] [unknown] [g] 0x00000000c0116e00 30.26% [guest/11094] [unknown] [g] 0xffffffff8100a288 43.69% [guest/10474] [unknown] [g] 0x00000000c0103d90 37.38% [guest/11399] [unknown] [g] 0xffffffff81600bc8 12.24% [guest/11094] [unknown] [g] 0xffffffff810aa91d 6.69% [guest/11094] [unknown] [u] 0x00007fa784d721c3 which is just pathetic. After a maddening 2 days sifting through perf minutia I found it -- id_hdr_size is not initialized for guest machines. This shows up on the report side as random garbage for the cpu and timestamp, e.g., 29816 7310572949125804849 0x1ac0 [0x50]: PERF_RECORD_MMAP ... That messes up the sample sorting such that synthesized guest maps are processed last. With this patch you get a much more helpful report: 12.11% [guest/11399] [guest.kernel.kallsyms.11399] [g] irqtime_account_process_tick 10.58% [guest/11399] [guest.kernel.kallsyms.11399] [g] run_timer_softirq 6.95% [guest/11094] [guest.kernel.kallsyms.11094] [g] printk_needs_cpu 6.50% [guest/11094] [guest.kernel.kallsyms.11094] [g] do_timer 6.45% [guest/11399] [guest.kernel.kallsyms.11399] [g] idle_balance 4.90% [guest/11094] [guest.kernel.kallsyms.11094] [g] native_read_tsc ... v2: - changed rbtree walk to use rb_first per Namhyung's suggestion Tested-by: Jiri Olsa Signed-off-by: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1342826756-64663-5-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c index 8668569d4b2a..16d783d322b6 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -729,3 +729,16 @@ char *machine__mmap_name(struct machine *self, char *bf, size_t size) return bf; } + +void machines__set_id_hdr_size(struct rb_root *machines, u16 id_hdr_size) +{ + struct rb_node *node; + struct machine *machine; + + for (node = rb_first(machines); node; node = rb_next(node)) { + machine = rb_entry(node, struct machine, rb_node); + machine->id_hdr_size = id_hdr_size; + } + + return; +} diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h index c14c665d9a25..03a1e9b08b21 100644 --- a/tools/perf/util/map.h +++ b/tools/perf/util/map.h @@ -151,6 +151,7 @@ struct machine *machines__add(struct rb_root *self, pid_t pid, struct machine *machines__find_host(struct rb_root *self); struct machine *machines__find(struct rb_root *self, pid_t pid); struct machine *machines__findnew(struct rb_root *self, pid_t pid); +void machines__set_id_hdr_size(struct rb_root *self, u16 id_hdr_size); char *machine__mmap_name(struct machine *self, char *bf, size_t size); int machine__init(struct machine *self, const char *root_dir, pid_t pid); void machine__exit(struct machine *self); diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 90ee39dd8ab2..8e4f0755d2aa 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -87,6 +87,7 @@ void perf_session__update_sample_type(struct perf_session *self) self->sample_id_all = perf_evlist__sample_id_all(self->evlist); self->id_hdr_size = perf_evlist__id_hdr_size(self->evlist); self->host_machine.id_hdr_size = self->id_hdr_size; + machines__set_id_hdr_size(&self->machines, self->id_hdr_size); } int perf_session__create_kernel_maps(struct perf_session *self)