From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 744D1C2D0EC for ; Fri, 10 Apr 2020 03:40:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 374DA206DD for ; Fri, 10 Apr 2020 03:40:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="k27oK0VR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726680AbgDJDkz (ORCPT ); Thu, 9 Apr 2020 23:40:55 -0400 Received: from mail-vk1-f201.google.com ([209.85.221.201]:42499 "EHLO mail-vk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726598AbgDJDky (ORCPT ); Thu, 9 Apr 2020 23:40:54 -0400 Received: by mail-vk1-f201.google.com with SMTP id n5so6585vkc.9 for ; Thu, 09 Apr 2020 20:40:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=qKfTfvUpUBcE6AJkXHIg7Cye2snFviZ5ra0HXoqUmUE=; b=k27oK0VRXwtNXyKntzkPxWqRkRG8PHvpiK2mJGBWbH6KzW5bytzfh7fVZj2AbPPGt7 r/oiGjP99gsmMBt5DiAQFU7kFq8Gyh3EkAiY3UeNZHRs1fOVAiAAoDSvgkoZHgcnKGY2 FSmhh5lVVxN/W6GhQt8n2ni+QnTzNlnVVmjaYw3ySJGVZhq+E1+NFmXvMhkDB/8ZAufB 0V6VmIzHYhpGtzDAYRBxPFPO0a+8HuTF2fex/SW6i996Er9r3QYKqTB1ed+sBOqy0DFL Dv3noaNPTxr2lyE7+6mw8ldLmMP2yT7zDpqxWPpIBMXhDFnOaLMpBpaLF+Mf9Dnsa9RM sJ3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=qKfTfvUpUBcE6AJkXHIg7Cye2snFviZ5ra0HXoqUmUE=; b=fHOhra4OmR2OQHoSf6etdo4Y9yICn1IyUZRyBdURsecJoubZSF8GNLkIle6aS0TFZ0 dUnn8z98/eM9t+cKM53jnj6t2IpwoAZjgPVD2GYxj5Ue1bnCtFvAVZVqacMZcgeCFprf a6eCpCG9SrC5hP/GZTzQgccULvc83yK0f8vmXo7P5wsv3Zzi/GA0iCyqMKLcpggb32pw RL55Pc/Urlu8/PjMtEx+JOrcwsOEhEPzdE8CfQ5HG057jujcNo0CwIAQ0FYb2qeQbd6t ijdq1hhbfEFDR3yGKCLIJKw6MSD+lFh9Bc4bfyXH854eoVF+VLId/1msOUpZ9IdM9Rt4 bRiw== X-Gm-Message-State: AGi0PuYSPXRF3rVxuz4jcyxDN/AbeE3wTYVVePVX4mW3yykERgH418JN tWUnE5rrxY/XIb6TSkNx1SxpyDKAD9X+ X-Google-Smtp-Source: APiQypJCTaxfKeTRqpQESflz34SoGqiU8t4IBKtPgmragWbXYyGCdL/Low10kAuARiAwiPuI4mz8S4hp7mk2 X-Received: by 2002:a05:6102:116d:: with SMTP id k13mr2306010vsg.79.1586490053294; Thu, 09 Apr 2020 20:40:53 -0700 (PDT) Date: Thu, 9 Apr 2020 20:40:47 -0700 Message-Id: <20200410034048.144150-1-irogers@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.26.0.110.g2183baf09c-goog Subject: [PATCH v3 1/2] tools api: add a lightweight buffered reading api From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Petr Mladek , Andrey Zhizhikin , Kefeng Wang , Thomas Gleixner , Kan Liang , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: Stephane Eranian , Ian Rogers Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The synthesize benchmark shows the majority of execution time going to fgets and sscanf, necessary to parse /proc/pid/maps. Add a new buffered reading library that will be used to replace these calls in a follow-up CL. Add tests for the library to perf test. Signed-off-by: Ian Rogers --- tools/lib/api/io.h | 112 ++++++++++++++++++++++++++++++++ tools/perf/tests/Build | 1 + tools/perf/tests/builtin-test.c | 4 ++ tools/perf/tests/tests.h | 1 + 4 files changed, 118 insertions(+) create mode 100644 tools/lib/api/io.h diff --git a/tools/lib/api/io.h b/tools/lib/api/io.h new file mode 100644 index 000000000000..b7e55b5f8a4a --- /dev/null +++ b/tools/lib/api/io.h @@ -0,0 +1,112 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Lightweight buffered reading library. + * + * Copyright 2019 Google LLC. + */ +#ifndef __API_IO__ +#define __API_IO__ + +struct io { + /* File descriptor being read/ */ + int fd; + /* Size of the read buffer. */ + unsigned int buf_len; + /* Pointer to storage for buffering read. */ + char *buf; + /* End of the storage. */ + char *end; + /* Currently accessed data pointer. */ + char *data; + /* Set true on when the end of file on read error. */ + bool eof; +}; + +static inline void io__init(struct io *io, int fd, + char *buf, unsigned int buf_len) +{ + io->fd = fd; + io->buf_len = buf_len; + io->buf = buf; + io->end = buf; + io->data = buf; + io->eof = false; +} + +/* Reads one character from the "io" file with similar semantics to fgetc. */ +static inline int io__get_char(struct io *io) +{ + char *ptr = io->data; + + if (io->eof) + return -1; + + if (ptr == io->end) { + ssize_t n = read(io->fd, io->buf, io->buf_len); + + if (n <= 0) { + io->eof = true; + return -1; + } + ptr = &io->buf[0]; + io->end = &io->buf[n]; + } + io->data = ptr + 1; + return *ptr; +} + +/* Read a hexadecimal value with no 0x prefix into the out argument hex. If the + * first character isn't hexadecimal returns -2, io->eof returns -1, otherwise + * returns the character after the hexadecimal value which may be -1 for eof. + * If the read value is larger than a u64 the high-order bits will be dropped. + */ +static inline int io__get_hex(struct io *io, __u64 *hex) +{ + bool first_read = true; + + *hex = 0; + while (true) { + int ch = io__get_char(io); + + if (ch < 0) + return ch; + if (ch >= '0' && ch <= '9') + *hex = (*hex << 4) | (ch - '0'); + else if (ch >= 'a' && ch <= 'f') + *hex = (*hex << 4) | (ch - 'a' + 10); + else if (ch >= 'A' && ch <= 'F') + *hex = (*hex << 4) | (ch - 'A' + 10); + else if (first_read) + return -2; + else + return ch; + first_read = false; + } +} + +/* Read a positive decimal value with out argument dec. If the first character + * isn't a decimal returns -2, io->eof returns -1, otherwise returns the + * character after the decimal value which may be -1 for eof. If the read value + * is larger than a u64 the high-order bits will be dropped. + */ +static inline int io__get_dec(struct io *io, __u64 *dec) +{ + bool first_read = true; + + *dec = 0; + while (true) { + int ch = io__get_char(io); + + if (ch < 0) + return ch; + if (ch >= '0' && ch <= '9') + *dec = (*dec * 10) + ch - '0'; + else if (first_read) + return -2; + else + return ch; + first_read = false; + } +} + +#endif /* __API_IO__ */ diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build index b3d1bf13ca07..c75557aeef0e 100644 --- a/tools/perf/tests/Build +++ b/tools/perf/tests/Build @@ -56,6 +56,7 @@ perf-y += mem2node.o perf-y += maps.o perf-y += time-utils-test.o perf-y += genelf.o +perf-y += api-io.o $(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c tests/Build $(call rule_mkdir) diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c index b6322eb0f423..3471ec52ea11 100644 --- a/tools/perf/tests/builtin-test.c +++ b/tools/perf/tests/builtin-test.c @@ -309,6 +309,10 @@ static struct test generic_tests[] = { .desc = "Test jit_write_elf", .func = test__jit_write_elf, }, + { + .desc = "Test api io", + .func = test__api_io, + }, { .desc = "maps__merge_in", .func = test__maps__merge_in, diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h index 61a1ab032080..d6d4ac34eeb7 100644 --- a/tools/perf/tests/tests.h +++ b/tools/perf/tests/tests.h @@ -112,6 +112,7 @@ int test__mem2node(struct test *t, int subtest); int test__maps__merge_in(struct test *t, int subtest); int test__time_utils(struct test *t, int subtest); int test__jit_write_elf(struct test *test, int subtest); +int test__api_io(struct test *test, int subtest); bool test__bp_signal_is_supported(void); bool test__bp_account_is_supported(void); -- 2.26.0.110.g2183baf09c-goog