Commit 5b7ba82a7591 ("perf symbols: Load kernel maps before using")
changed it so that loading a kernel dso would cause the symbols for
the dso to be eagerly loaded. For perf record this is overhead as the
symbols won't be used. Add a symbol_conf to control the behavior and
disable it for perf record and perf inject.
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/builtin-inject.c | 4 ++++
tools/perf/builtin-record.c | 2 ++
tools/perf/util/event.c | 4 ++--
tools/perf/util/symbol_conf.h | 3 ++-
4 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index c8cf2fdd9cff..1539fb18c749 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -2265,6 +2265,10 @@ int cmd_inject(int argc, const char **argv)
"perf inject [<options>]",
NULL
};
+
+ /* Disable eager loading of kernel symbols that adds overhead to perf inject. */
+ symbol_conf.lazy_load_kernel_maps = true;
+
#ifndef HAVE_JITDUMP
set_option_nobuild(options, 'j', "jit", "NO_LIBELF=1", true);
#endif
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index dcf288a4fb9a..8ec818568662 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -3989,6 +3989,8 @@ int cmd_record(int argc, const char **argv)
# undef set_nobuild
#endif
+ /* Disable eager loading of kernel symbols that adds overhead to perf record. */
+ symbol_conf.lazy_load_kernel_maps = true;
rec->opts.affinity = PERF_AFFINITY_SYS;
rec->evlist = evlist__new();
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 923c0fb15122..68f45e9e63b6 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -617,13 +617,13 @@ struct map *thread__find_map(struct thread *thread, u8 cpumode, u64 addr,
if (cpumode == PERF_RECORD_MISC_KERNEL && perf_host) {
al->level = 'k';
maps = machine__kernel_maps(machine);
- load_map = true;
+ load_map = !symbol_conf.lazy_load_kernel_maps;
} else if (cpumode == PERF_RECORD_MISC_USER && perf_host) {
al->level = '.';
} else if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) {
al->level = 'g';
maps = machine__kernel_maps(machine);
- load_map = true;
+ load_map = !symbol_conf.lazy_load_kernel_maps;
} else if (cpumode == PERF_RECORD_MISC_GUEST_USER && perf_guest) {
al->level = 'u';
} else {
diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h
index 0b589570d1d0..2b2fb9e224b0 100644
--- a/tools/perf/util/symbol_conf.h
+++ b/tools/perf/util/symbol_conf.h
@@ -42,7 +42,8 @@ struct symbol_conf {
inline_name,
disable_add2line_warn,
buildid_mmap2,
- guest_code;
+ guest_code,
+ lazy_load_kernel_maps;
const char *vmlinux_name,
*kallsyms_name,
*source_prefix,
--
2.42.0.609.gbb76f46606-goog
