Current perf report is real slow on newer kernels,
with following commit:
c0f3ea158939 ("stop using '%pK' for /proc/kallsyms pointer values")
which prevent pointers in /proc/kallsyms, in case
kernel.perf_event_paranoid=2.
That makes perf to fail in finding kernel map details,
and keep parsing it again for every kernel sample.
Adding and setting a new machine::vmlinux_maps_failed
flag after first failed parsing attempt and using it
to prevent new pointless parsing.
TODO We might want to add some perf report warning
about that.
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Jiri Olsa <[email protected]>
---
tools/perf/util/machine.c | 6 ++++--
tools/perf/util/machine.h | 1 +
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index b05a67464c03..5e9648817077 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1222,13 +1222,15 @@ int machine__create_kernel_maps(struct machine *machine)
u64 addr = 0;
int ret;
- if (kernel == NULL)
+ if (kernel == NULL || machine->vmlinux_maps_failed)
return -1;
ret = __machine__create_kernel_maps(machine, kernel);
dso__put(kernel);
- if (ret < 0)
+ if (ret < 0) {
+ machine->vmlinux_maps_failed = true;
return -1;
+ }
if (symbol_conf.use_modules && machine__create_modules(machine) < 0) {
if (machine__is_host(machine))
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index 5ce860b64c74..edcb007333cb 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -42,6 +42,7 @@ struct machine {
u16 id_hdr_size;
bool comm_exec;
bool kptr_restrict_warned;
+ bool vmlinux_maps_failed;
char *root_dir;
struct threads threads[THREADS__TABLE_SIZE];
struct vdso_info *vdso_info;
--
2.13.6
