perf report: Use properly build_id kernel binaries
If we bring the recorded perf data together with kernel binary from another
machine using:
on server A:
perf archive
on server B:
tar xjvf perf.data.tar.bz2 -C ~/.debug
the build_id kernel dso is not properly recognized during the "perf report"
command on server B.
The reason is, that build_id dsos are added during the session initialization,
while the kernel maps are created during the sample event processing.
The machine__create_kernel_maps functions ends up creating new dso object for
kernel, but it does not check if we already have one added by build_id
processing.
Also the build_id reading ABI quirk added in commit:
- commit b25114817a73bbd2b84ce9dba02ee1ef8989a947
perf build-id: Add quirk to deal with perf.data file format breakage
populates the "struct build_id_event::pid" with 0, which
is later interpreted as DEFAULT_GUEST_KERNEL_ID.
This is not always correct, so it's better to guess the pid
value based on the "struct build_id_event::header::misc" value.
- Tested with data generated on x86 kernel version v2.6.34
and reported back on x86_64 current kernel.
- Not tested for guest kernel case.
Note the problem stays for PERF_RECORD_MMAP events recorded by perf that
does not use proper pid (HOST_KERNEL_ID/DEFAULT_GUEST_KERNEL_ID). They are
misinterpreted within the current perf code. Probably there's not much we
can do about that.
Cc: Avi Kivity <avi@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Link: http://lkml.kernel.org/r/20110601194346.GB1934@jolsa.brq.redhat.com
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index d4f3101..b6c1ad1 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -726,7 +726,16 @@
return -1;
bev.header = old_bev.header;
- bev.pid = 0;
+
+ /*
+ * As the pid is the missing value, we need to fill
+ * it properly. The header.misc value give us nice hint.
+ */
+ bev.pid = HOST_KERNEL_ID;
+ if (bev.header.misc == PERF_RECORD_MISC_GUEST_USER ||
+ bev.header.misc == PERF_RECORD_MISC_GUEST_KERNEL)
+ bev.pid = DEFAULT_GUEST_KERNEL_ID;
+
memcpy(bev.build_id, old_bev.build_id, sizeof(bev.build_id));
__event_process_build_id(&bev, filename, session);
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index a8b5371..e142c21 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -2181,27 +2181,22 @@
return ret;
}
-struct dso *dso__new_kernel(const char *name)
+static struct dso*
+dso__kernel_findnew(struct machine *machine, const char *name,
+ const char *short_name, int dso_type)
{
- struct dso *dso = dso__new(name ?: "[kernel.kallsyms]");
+ /*
+ * The kernel dso could be created by build_id processing.
+ */
+ struct dso *dso = __dsos__findnew(&machine->kernel_dsos, name);
+ /*
+ * We need to run this in all cases, since during the build_id
+ * processing we had no idea this was the kernel dso.
+ */
if (dso != NULL) {
- dso__set_short_name(dso, "[kernel]");
- dso->kernel = DSO_TYPE_KERNEL;
- }
-
- return dso;
-}
-
-static struct dso *dso__new_guest_kernel(struct machine *machine,
- const char *name)
-{
- char bf[PATH_MAX];
- struct dso *dso = dso__new(name ?: machine__mmap_name(machine, bf,
- sizeof(bf)));
- if (dso != NULL) {
- dso__set_short_name(dso, "[guest.kernel]");
- dso->kernel = DSO_TYPE_GUEST_KERNEL;
+ dso__set_short_name(dso, short_name);
+ dso->kernel = dso_type;
}
return dso;
@@ -2219,24 +2214,36 @@
dso->has_build_id = true;
}
-static struct dso *machine__create_kernel(struct machine *machine)
+static struct dso *machine__get_kernel(struct machine *machine)
{
const char *vmlinux_name = NULL;
struct dso *kernel;
if (machine__is_host(machine)) {
vmlinux_name = symbol_conf.vmlinux_name;
- kernel = dso__new_kernel(vmlinux_name);
+ if (!vmlinux_name)
+ vmlinux_name = "[kernel.kallsyms]";
+
+ kernel = dso__kernel_findnew(machine, vmlinux_name,
+ "[kernel]",
+ DSO_TYPE_KERNEL);
} else {
+ char bf[PATH_MAX];
+
if (machine__is_default_guest(machine))
vmlinux_name = symbol_conf.default_guest_vmlinux_name;
- kernel = dso__new_guest_kernel(machine, vmlinux_name);
+ if (!vmlinux_name)
+ vmlinux_name = machine__mmap_name(machine, bf,
+ sizeof(bf));
+
+ kernel = dso__kernel_findnew(machine, vmlinux_name,
+ "[guest.kernel]",
+ DSO_TYPE_GUEST_KERNEL);
}
- if (kernel != NULL) {
+ if (kernel != NULL && (!kernel->has_build_id))
dso__read_running_kernel_build_id(kernel, machine);
- dsos__add(&machine->kernel_dsos, kernel);
- }
+
return kernel;
}
@@ -2340,7 +2347,7 @@
int machine__create_kernel_maps(struct machine *machine)
{
- struct dso *kernel = machine__create_kernel(machine);
+ struct dso *kernel = machine__get_kernel(machine);
if (kernel == NULL ||
__machine__create_kernel_maps(machine, kernel) < 0)
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 325ee36..4f377d9 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -155,7 +155,6 @@
};
struct dso *dso__new(const char *name);
-struct dso *dso__new_kernel(const char *name);
void dso__delete(struct dso *dso);
int dso__name_len(const struct dso *dso);