From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 119F818AE1; Thu, 19 Oct 2023 11:02:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="glxnQJzH" Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A586A112; Thu, 19 Oct 2023 04:02:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1697713335; x=1729249335; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=dS7MBxgFMsSLS+p8OyIgAOLuaoqyA0fOLFfs16p9U9o=; b=glxnQJzHnwK2nGIZx0u9JSK8g1exn4Kp+xckDxFnk2uuCNqnyZu0r+XX Y8h2FWMs/hpZRD07WmNyzGoQYi4EJVmeKuuWzpj6XA+BNyxcgI9PlMJd4 hO8kG5OmW2uh3SBK+kWmC0OUMz/lrTMMilS9GGo2cROmT2UjeKlFp/SbQ 76qNU4EXMPfnrgVuz/MG9PIteX8KGRfz4u/JZ3+V4g4MzhV4KoR4zi6Rz MDqVxSnpBsG4TW9zQmsxK27jkQa0t3v8OpwcEubZKYZAg1SahrWyxUgju PCVElCGkuqQfuDa9fm6w4psd/5rfgHb53eCYfh/ZvLFYKgWeUxwNqaPOx w==; X-IronPort-AV: E=McAfee;i="6600,9927,10867"; a="366464129" X-IronPort-AV: E=Sophos;i="6.03,237,1694761200"; d="scan'208";a="366464129" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2023 04:02:15 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10867"; a="760603065" X-IronPort-AV: E=Sophos;i="6.03,237,1694761200"; d="scan'208";a="760603065" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.249.39.14]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2023 04:02:09 -0700 Message-ID: Date: Thu, 19 Oct 2023 14:02:06 +0300 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 10/13] perf record: Lazy load kernel symbols Content-Language: en-US To: Ian Rogers , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Nick Terrell , Kan Liang , Song Liu , Sandipan Das , Anshuman Khandual , James Clark , Liam Howlett , Miguel Ojeda , Leo Yan , German Gomez , Ravi Bangoria , Artem Savkov , Athira Rajeev , Andi Kleen , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, bpf@vger.kernel.org References: <20231012062359.1616786-1-irogers@google.com> <20231012062359.1616786-11-irogers@google.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: <20231012062359.1616786-11-irogers@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/10/23 09:23, 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 > --- > 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 []", > NULL > }; > + > + /* Disable eager loading of kernel symbols that adds overhead to perf inject. */ > + symbol_conf.lazy_load_kernel_maps = true; Possibly not for itrace kernel decoding, so: if (!inject->itrace_synth_opts.set) 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,