diff mbox series

[v4,02/53] perf record: Lazy load kernel symbols

Message ID 20231102175735.2272696-3-irogers@google.com
State New
Headers
Series Improvements to memory use |

Commit Message

Ian Rogers Nov. 2, 2023, 5:56 p.m. UTC 
  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@google.com>
---
 tools/perf/builtin-inject.c   | 6 ++++++
 tools/perf/builtin-record.c   | 2 ++
 tools/perf/util/event.c       | 4 ++--
 tools/perf/util/symbol_conf.h | 3 ++-
 4 files changed, 12 insertions(+), 3 deletions(-)

Comments

Namhyung Kim Nov. 5, 2023, 5:34 p.m. UTC | #1 
On Thu, Nov 2, 2023 at 10:58 AM Ian Rogers <irogers@google.com> wrote:
>
> 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@google.com>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung

> ---
>  tools/perf/builtin-inject.c   | 6 ++++++
>  tools/perf/builtin-record.c   | 2 ++
>  tools/perf/util/event.c       | 4 ++--
>  tools/perf/util/symbol_conf.h | 3 ++-
>  4 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index c8cf2fdd9cff..eb3ef5c24b66 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -2265,6 +2265,12 @@ int cmd_inject(int argc, const char **argv)
>                 "perf inject [<options>]",
>                 NULL
>         };
> +
> +       if (!inject.itrace_synth_opts.set) {
> +               /* 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,
> --
> 2.42.0.869.gea05f2083d-goog
>
Adrian Hunter Nov. 6, 2023, 11 a.m. UTC | #2 
On 2/11/23 19:56, Ian Rogers wrote:
> 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@google.com>

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
>  tools/perf/builtin-inject.c   | 6 ++++++
>  tools/perf/builtin-record.c   | 2 ++
>  tools/perf/util/event.c       | 4 ++--
>  tools/perf/util/symbol_conf.h | 3 ++-
>  4 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index c8cf2fdd9cff..eb3ef5c24b66 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -2265,6 +2265,12 @@ int cmd_inject(int argc, const char **argv)
>  		"perf inject [<options>]",
>  		NULL
>  	};
> +
> +	if (!inject.itrace_synth_opts.set) {
> +		/* 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,
Arnaldo Carvalho de Melo Nov. 8, 2023, 4:01 p.m. UTC | #3 
Em Mon, Nov 06, 2023 at 01:00:14PM +0200, Adrian Hunter escreveu:
> On 2/11/23 19:56, Ian Rogers wrote:
> > 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@google.com>
 
> Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>

Thanks, applied to perf-tools-next.

- Arnaldo
diff mbox series

Patch

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index c8cf2fdd9cff..eb3ef5c24b66 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -2265,6 +2265,12 @@  int cmd_inject(int argc, const char **argv)
 		"perf inject [<options>]",
 		NULL
 	};
+
+	if (!inject.itrace_synth_opts.set) {
+		/* 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,