tools api: Add a lightweight buffered reading api
authorIan Rogers <irogers@google.com>
Wed, 15 Apr 2020 05:40:49 +0000 (22:40 -0700)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Thu, 30 Apr 2020 13:48:28 +0000 (10:48 -0300)
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.

Committer tests:

  $ perf test api
  63: Test api io                                           : Ok
  $

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrey Zhizhikin <andrey.z@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/lkml/20200415054050.31645-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/lib/api/io.h [new file with mode: 0644]
tools/perf/tests/Build
tools/perf/tests/api-io.c [new file with mode: 0644]
tools/perf/tests/builtin-test.c
tools/perf/tests/tests.h

diff --git a/tools/lib/api/io.h b/tools/lib/api/io.h
new file mode 100644 (file)
index 0000000..b7e55b5
--- /dev/null
@@ -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__ */
index b3d1bf1..c75557a 100644 (file)
@@ -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/api-io.c b/tools/perf/tests/api-io.c
new file mode 100644 (file)
index 0000000..2ada86a
--- /dev/null
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "debug.h"
+#include "tests.h"
+#include <api/io.h>
+#include <linux/kernel.h>
+
+#define TEMPL "/tmp/perf-test-XXXXXX"
+
+#define EXPECT_EQUAL(val, expected)                             \
+do {                                                           \
+       if (val != expected) {                                  \
+               pr_debug("%s:%d: %d != %d\n",                   \
+                       __FILE__, __LINE__, val, expected);     \
+               ret = -1;                                       \
+       }                                                       \
+} while (0)
+
+#define EXPECT_EQUAL64(val, expected)                           \
+do {                                                           \
+       if (val != expected) {                                  \
+               pr_debug("%s:%d: %lld != %lld\n",               \
+                       __FILE__, __LINE__, val, expected);     \
+               ret = -1;                                       \
+       }                                                       \
+} while (0)
+
+static int make_test_file(char path[PATH_MAX], const char *contents)
+{
+       ssize_t contents_len = strlen(contents);
+       int fd;
+
+       strcpy(path, TEMPL);
+       fd = mkstemp(path);
+       if (fd < 0) {
+               pr_debug("mkstemp failed");
+               return -1;
+       }
+       if (write(fd, contents, contents_len) < contents_len) {
+               pr_debug("short write");
+               close(fd);
+               unlink(path);
+               return -1;
+       }
+       close(fd);
+       return 0;
+}
+
+static int setup_test(char path[PATH_MAX], const char *contents,
+                     size_t buf_size, struct io *io)
+{
+       if (make_test_file(path, contents))
+               return -1;
+
+       io->fd = open(path, O_RDONLY);
+       if (io->fd < 0) {
+               pr_debug("Failed to open '%s'\n", path);
+               unlink(path);
+               return -1;
+       }
+       io->buf = malloc(buf_size);
+       if (io->buf == NULL) {
+               pr_debug("Failed to allocate memory");
+               close(io->fd);
+               unlink(path);
+               return -1;
+       }
+       io__init(io, io->fd, io->buf, buf_size);
+       return 0;
+}
+
+static void cleanup_test(char path[PATH_MAX], struct io *io)
+{
+       free(io->buf);
+       close(io->fd);
+       unlink(path);
+}
+
+static int do_test_get_char(const char *test_string, size_t buf_size)
+{
+       char path[PATH_MAX];
+       struct io io;
+       int ch, ret = 0;
+       size_t i;
+
+       if (setup_test(path, test_string, buf_size, &io))
+               return -1;
+
+       for (i = 0; i < strlen(test_string); i++) {
+               ch = io__get_char(&io);
+
+               EXPECT_EQUAL(ch, test_string[i]);
+               EXPECT_EQUAL(io.eof, false);
+       }
+       ch = io__get_char(&io);
+       EXPECT_EQUAL(ch, -1);
+       EXPECT_EQUAL(io.eof, true);
+
+       cleanup_test(path, &io);
+       return ret;
+}
+
+static int test_get_char(void)
+{
+       int i, ret = 0;
+       size_t j;
+
+       static const char *const test_strings[] = {
+               "12345678abcdef90",
+               "a\nb\nc\nd\n",
+               "\a\b\t\v\f\r",
+       };
+       for (i = 0; i <= 10; i++) {
+               for (j = 0; j < ARRAY_SIZE(test_strings); j++) {
+                       if (do_test_get_char(test_strings[j], 1 << i))
+                               ret = -1;
+               }
+       }
+       return ret;
+}
+
+static int do_test_get_hex(const char *test_string,
+                       __u64 val1, int ch1,
+                       __u64 val2, int ch2,
+                       __u64 val3, int ch3,
+                       bool end_eof)
+{
+       char path[PATH_MAX];
+       struct io io;
+       int ch, ret = 0;
+       __u64 hex;
+
+       if (setup_test(path, test_string, 4, &io))
+               return -1;
+
+       ch = io__get_hex(&io, &hex);
+       EXPECT_EQUAL64(hex, val1);
+       EXPECT_EQUAL(ch, ch1);
+
+       ch = io__get_hex(&io, &hex);
+       EXPECT_EQUAL64(hex, val2);
+       EXPECT_EQUAL(ch, ch2);
+
+       ch = io__get_hex(&io, &hex);
+       EXPECT_EQUAL64(hex, val3);
+       EXPECT_EQUAL(ch, ch3);
+
+       EXPECT_EQUAL(io.eof, end_eof);
+
+       cleanup_test(path, &io);
+       return ret;
+}
+
+static int test_get_hex(void)
+{
+       int ret = 0;
+
+       if (do_test_get_hex("12345678abcdef90",
+                               0x12345678abcdef90, -1,
+                               0, -1,
+                               0, -1,
+                               true))
+               ret = -1;
+
+       if (do_test_get_hex("1\n2\n3\n",
+                               1, '\n',
+                               2, '\n',
+                               3, '\n',
+                               false))
+               ret = -1;
+
+       if (do_test_get_hex("12345678ABCDEF90;a;b",
+                               0x12345678abcdef90, ';',
+                               0xa, ';',
+                               0xb, -1,
+                               true))
+               ret = -1;
+
+       if (do_test_get_hex("0x1x2x",
+                               0, 'x',
+                               1, 'x',
+                               2, 'x',
+                               false))
+               ret = -1;
+
+       if (do_test_get_hex("x1x",
+                               0, -2,
+                               1, 'x',
+                               0, -1,
+                               true))
+               ret = -1;
+
+       if (do_test_get_hex("10000000000000000000000000000abcdefgh99i",
+                               0xabcdef, 'g',
+                               0, -2,
+                               0x99, 'i',
+                               false))
+               ret = -1;
+
+       return ret;
+}
+
+static int do_test_get_dec(const char *test_string,
+                       __u64 val1, int ch1,
+                       __u64 val2, int ch2,
+                       __u64 val3, int ch3,
+                       bool end_eof)
+{
+       char path[PATH_MAX];
+       struct io io;
+       int ch, ret = 0;
+       __u64 dec;
+
+       if (setup_test(path, test_string, 4, &io))
+               return -1;
+
+       ch = io__get_dec(&io, &dec);
+       EXPECT_EQUAL64(dec, val1);
+       EXPECT_EQUAL(ch, ch1);
+
+       ch = io__get_dec(&io, &dec);
+       EXPECT_EQUAL64(dec, val2);
+       EXPECT_EQUAL(ch, ch2);
+
+       ch = io__get_dec(&io, &dec);
+       EXPECT_EQUAL64(dec, val3);
+       EXPECT_EQUAL(ch, ch3);
+
+       EXPECT_EQUAL(io.eof, end_eof);
+
+       cleanup_test(path, &io);
+       return ret;
+}
+
+static int test_get_dec(void)
+{
+       int ret = 0;
+
+       if (do_test_get_dec("12345678abcdef90",
+                               12345678, 'a',
+                               0, -2,
+                               0, -2,
+                               false))
+               ret = -1;
+
+       if (do_test_get_dec("1\n2\n3\n",
+                               1, '\n',
+                               2, '\n',
+                               3, '\n',
+                               false))
+               ret = -1;
+
+       if (do_test_get_dec("12345678;1;2",
+                               12345678, ';',
+                               1, ';',
+                               2, -1,
+                               true))
+               ret = -1;
+
+       if (do_test_get_dec("0x1x2x",
+                               0, 'x',
+                               1, 'x',
+                               2, 'x',
+                               false))
+               ret = -1;
+
+       if (do_test_get_dec("x1x",
+                               0, -2,
+                               1, 'x',
+                               0, -1,
+                               true))
+               ret = -1;
+
+       if (do_test_get_dec("10000000000000000000000000000000000000000000000000000000000123456789ab99c",
+                               123456789, 'a',
+                               0, -2,
+                               99, 'c',
+                               false))
+               ret = -1;
+
+       return ret;
+}
+
+int test__api_io(struct test *test __maybe_unused,
+               int subtest __maybe_unused)
+{
+       int ret = 0;
+
+       if (test_get_char())
+               ret = TEST_FAIL;
+       if (test_get_hex())
+               ret = TEST_FAIL;
+       if (test_get_dec())
+               ret = TEST_FAIL;
+       return ret;
+}
index b6322eb..3471ec5 100644 (file)
@@ -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,
index 61a1ab0..d6d4ac3 100644 (file)
@@ -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);