perf: Add support for full Intel event lists v3

From: Andi Kleen <[email protected]>

I need a JSON parser. This adds the simplest JSON parser I could find -- Serge Zaitsev's jsmn `jasmine' -- to the perf library. I merely converted it to (mostly) Linux style and added support for non 0 terminated input.

The parser is quite straight forward and does not copy any data, just returns tokens with offsets into the input buffer. So it's relatively efficient and simple to use.

The code is not fully checkpatch clean, but I didn't want to completely fork the upstream code.

Original source: http://zserge.bitbucket.org/jsmn.html

In addition I added a simple wrapper that mmaps a json file and provides some straight forward access functions.

Used in follow-on patches to parse event files.

Signed-off-by Andi Kleen <[email protected]>

---
 tools/perf/Makefile.perf |   4 +
 tools/perf/util/jsmn.c   | 297 +++++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/jsmn.h   |  65 +++++++++++
 tools/perf/util/json.c   | 155 +++++++++++++++++++++++++
 tools/perf/util/json.h   |  13 +++
 5 files changed, 534 insertions(+)
 create mode 100644 tools/perf/util/jsmn.c
 create mode 100644 tools/perf/util/jsmn.h
 create mode 100644 tools/perf/util/json.c
 create mode 100644 tools/perf/util/json.h

tools/perf/Makefile.perf +4 -0

index 2baf61c..43d4109 100644
@@ -300,6 +300,8 @@ LIB_H += ui/progress.h
 LIB_H += ui/util.h
 LIB_H += ui/ui.h
 LIB_H += util/data.h
+LIB_H += util/jsmn.h
+LIB_H += util/json.h
 
 LIB_OBJS += $(OUTPUT)util/abspath.o
 LIB_OBJS += $(OUTPUT)util/alias.o

@@ -373,6 +375,8 @@ LIB_OBJS += $(OUTPUT)util/stat.o
 LIB_OBJS += $(OUTPUT)util/record.o
 LIB_OBJS += $(OUTPUT)util/srcline.o
 LIB_OBJS += $(OUTPUT)util/data.o
+LIB_OBJS += $(OUTPUT)util/jsmn.o
+LIB_OBJS += $(OUTPUT)util/json.o
 
 LIB_OBJS += $(OUTPUT)ui/setup.o
 LIB_OBJS += $(OUTPUT)ui/helpline.o

tools/perf/util/jsmn.c new file +19 -0

new file mode 100644
index 0000000..3e4b711
@@ -0,0 +1,297 @@
+/*
+ * Copyright (c) 2010 Serge A. Zaitsev
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

tools/perf/util/jsmn.c new file +14 -0

+ */
+static jsmntok_t *jsmn_alloc_token(jsmn_parser *parser,
+				   jsmntok_t *tokens, size_t num_tokens)
+{
+	jsmntok_t *tok;
+
+	if ((unsigned)parser->toknext >= num_tokens)
+		return NULL;
+	tok = &tokens[parser->toknext++];
+	tok->start = tok->end = -1;
+	tok->size = 0;
+	return tok;
+}
+

tools/perf/util/jsmn.c new file +7 -0

+}
+
+/*
+ * Fills next available token with JSON primitive.
+ */
+static jsmnerr_t jsmn_parse_primitive(jsmn_parser *parser, const char *js,
+				      size_t len,

tools/perf/util/jsmn.c new file +29 -0

+		/*
+		 * In strict mode primitive must be followed by ","
+		 * or "}" or "]"
+		 */
+		case ':':
+#endif
+		case '\t':
+		case '\r':
+		case '\n':
+		case ' ':
+		case ',':
+		case ']':
+		case '}':
+			goto found;
+		default:
+			break;
+		}
+		if (js[parser->pos] < 32 || js[parser->pos] >= 127) {
+			parser->pos = start;
+			return JSMN_ERROR_INVAL;
+		}
+	}
+#ifdef JSMN_STRICT
+	/*
+	 * In strict mode primitive must be followed by a
+	 * comma/object/array.
+	 */
+	parser->pos = start;
+	return JSMN_ERROR_PART;

tools/perf/util/jsmn.c new file +6 -0

+	return JSMN_SUCCESS;
+}
+
+/*
+ * Fills next token with JSON string.
+ */

tools/perf/util/jsmn.c new file +40 -0

+	for (; parser->pos < len; parser->pos++) {
+		char c = js[parser->pos];
+
+		/* Quote: end of string */
+		if (c == '\"') {
+			token = jsmn_alloc_token(parser, tokens, num_tokens);
+			if (token == NULL) {
+				parser->pos = start;
+				return JSMN_ERROR_NOMEM;
+			}
+			jsmn_fill_token(token, JSMN_STRING, start+1,
+					parser->pos);
+			return JSMN_SUCCESS;
+		}
+
+		/* Backslash: Quoted symbol expected */
+		if (c == '\\') {
+			parser->pos++;
+			switch (js[parser->pos]) {
+				/* Allowed escaped symbols */
+			case '\"':
+			case '/':
+			case '\\':
+			case 'b':
+			case 'f':
+			case 'r':
+			case 'n':
+			case 't':
+				break;
+				/* Allows escaped symbol \uXXXX */
+			case 'u':
+				/* TODO */
+				break;
+				/* Unexpected symbol */
+			default:
+				parser->pos = start;
+				return JSMN_ERROR_INVAL;
+			}
+		}
+	}

tools/perf/util/jsmn.c new file +8 -0

+{
+	jsmnerr_t r;
+	int i;
+	jsmntok_t *token;
+
+	for (; parser->pos < len; parser->pos++) {
+		char c;
+		jsmntype_t type;

tools/perf/util/jsmn.c new file +84 -0

+					if (token->type != type)
+						return JSMN_ERROR_INVAL;
+					parser->toksuper = -1;
+					token->end = parser->pos + 1;
+					break;
+				}
+			}
+			/* Error if unmatched closing bracket */
+			if (i == -1)
+				return JSMN_ERROR_INVAL;
+			for (; i >= 0; i--) {
+				token = &tokens[i];
+				if (token->start != -1 && token->end == -1) {
+					parser->toksuper = i;
+					break;
+				}
+			}
+			break;
+		case '\"':
+			r = jsmn_parse_string(parser, js, len, tokens,
+					      num_tokens);
+			if (r < 0)
+				return r;
+			if (parser->toksuper != -1)
+				tokens[parser->toksuper].size++;
+			break;
+		case '\t':
+		case '\r':
+		case '\n':
+		case ':':
+		case ',':
+		case ' ':
+			break;
+#ifdef JSMN_STRICT
+			/*
+			 * In strict mode primitives are:
+			 * numbers and booleans.
+			 */
+		case '-':
+		case '0':
+		case '1':
+		case '2':
+		case '3':
+		case '4':
+		case '5':
+		case '6':
+		case '7':
+		case '8':
+		case '9':
+		case 't':
+		case 'f':
+		case 'n':
+#else
+			/*
+			 * In non-strict mode every unquoted value
+			 * is a primitive.
+			 */
+		default:
+#endif
+			r = jsmn_parse_primitive(parser, js, len, tokens,
+						 num_tokens);
+			if (r < 0)
+				return r;
+			if (parser->toksuper != -1)
+				tokens[parser->toksuper].size++;
+			break;
+
+#ifdef JSMN_STRICT
+			/* Unexpected char in strict mode */
+		default:
+			return JSMN_ERROR_INVAL;
+#endif
+		}
+	}
+
+	for (i = parser->toknext - 1; i >= 0; i--) {
+		/* Unmatched opened object or array */
+		if (tokens[i].start != -1 && tokens[i].end == -1)
+			return JSMN_ERROR_PART;
+	}
+
+	return JSMN_SUCCESS;
+}
+

tools/perf/util/jsmn.h new file +17 -0

new file mode 100644
index 0000000..8f432b0
@@ -0,0 +1,65 @@
+#ifndef __JSMN_H_
+#define __JSMN_H_
+
+/*
+ * JSON type identifier. Basic types are:
+ *	o Object
+ *	o Array
+ *	o String
+ *	o Other primitive: number, boolean (true/false) or null
+ */
+typedef enum {
+	JSMN_PRIMITIVE = 0,
+	JSMN_OBJECT = 1,
+	JSMN_ARRAY = 2,
+	JSMN_STRING = 3
+} jsmntype_t;
+

tools/perf/util/jsmn.h new file +32 -0

+ */
+typedef struct {
+	jsmntype_t type;
+	int start;
+	int end;
+	int size;
+} jsmntok_t;
+
+/*
+ * JSON parser. Contains an array of token blocks available. Also stores
+ * the string being parsed now and current position in that string
+ */
+typedef struct {
+	unsigned int pos; /* offset in the JSON string */
+	int toknext; /* next token to allocate */
+	int toksuper; /* superior token node, e.g parent object or array */
+} jsmn_parser;
+
+/*
+ * Create JSON parser over an array of tokens
+ */
+void jsmn_init(jsmn_parser *parser);
+
+/*
+ * Run JSON parser. It parses a JSON data string into and array of tokens,
+ * each describing a single JSON object.
+ */
+jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js,
+		     size_t len,
+		     jsmntok_t *tokens, unsigned int num_tokens);
+
+#endif /* __JSMN_H_ */

tools/perf/util/json.c new file +34 -0

new file mode 100644
index 0000000..e505da9
@@ -0,0 +1,155 @@
+/* Parse JSON files using the JSMN parser. */
+
+/*
+ * Copyright (c) 2014, Intel Corporation
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>

tools/perf/util/json.c new file +8 -0

+}
+
+/*
+ * Parse json file using jsmn. Return array of tokens,
+ * and mapped file. Caller needs to free array.
+ */
+jsmntok_t *parse_json(const char *fn, char **map, size_t *size, int *len)
+{

tools/perf/util/json.c new file +50 -0

+	if (res != JSMN_SUCCESS) {
+		pr_err("%s: json error %d\n", fn, res);
+		goto error_free;
+	}
+	if (len)
+		*len = parser.toknext;
+	return tokens;
+error_free:
+	free(tokens);
+error:
+	unmapfile(*map, *size);
+	return NULL;
+}
+
+void free_json(char *map, size_t size, jsmntok_t *tokens)
+{
+	free(tokens);
+	unmapfile(map, size);
+}
+
+static int countchar(char *map, char c, int end)
+{
+	int i;
+	int count = 0;
+	for (i = 0; i < end; i++)
+		if (map[i] == c)
+			count++;
+	return count;
+}
+
+/* Return line number of a jsmn token */
+int json_line(char *map, jsmntok_t *t)
+{
+	return countchar(map, '\n', t->start) + 1;
+}
+
+static const char *jsmn_types[] = {
+	[JSMN_PRIMITIVE] = "primitive",
+	[JSMN_ARRAY] = "array",
+	[JSMN_OBJECT] = "object",
+	[JSMN_STRING] = "string"
+};
+
+#define LOOKUP(a, i) ((i) < (sizeof(a)/sizeof(*(a))) ? ((a)[i]) : "?")
+
+/* Return type name of a jsmn token */
+const char *json_name(jsmntok_t *t)
+{
+	return LOOKUP(jsmn_types, t->type);
+}

tools/perf/util/json.c new file +2 -0

+	return len == strlen(s) && !strncasecmp(map + t->start, s, len);
+}

tools/perf/util/json.h new file +13 -0

new file mode 100644
index 0000000..37dd9e9
@@ -0,0 +1,13 @@
+#ifndef JSON_H
+#define JSON_H 1
+
+#include "jsmn.h"
+
+jsmntok_t *parse_json(const char *fn, char **map, size_t *size, int *len);
+void free_json(char *map, size_t size, jsmntok_t *tokens);
+int json_line(char *map, jsmntok_t *t);
+const char *json_name(jsmntok_t *t);
+int json_streq(char *map, jsmntok_t *t, const char *s);
+int json_len(jsmntok_t *t);
+
+#endif

Hi Andi,

Quoted 6 lines · Andi Kleen

From: Andi Kleen <[email protected]>

I need a JSON parser. This adds the simplest JSON parser I could find -- Serge Zaitsev's jsmn `jasmine' -- to the perf library. I merely converted it to (mostly) Linux style and added support for non 0 terminated input.

It seems like the original code now also supports it.

From: Andi Kleen <[email protected]>

Add a parser for Intel style JSON event files. This allows to use an Intel event list directly with perf. The Intel event lists can be quite large and are too big to store in unswappable kernel memory.

The parser code knows how to convert the JSON fields
to perf fields. The conversion code is straight forward. It knows (very little) Intel specific information, and can be easily extended to handle fields for other CPUs.

The parser code is partially shared with an independent parsing library, which is 2-clause BSD licenced. To avoid any conflicts I marked those files as BSD licenced too. As part of perf they become GPLv2.

The events are handled using the existing alias machinery.

We output the BriefDescription in perf list.

Right now the json file can be specified as an argument to perf stat/record/list. Followon patches will automate this.

Signed-off-by Andi Kleen <[email protected]>

---
 tools/perf/Documentation/perf-list.txt   |   6 +
 tools/perf/Documentation/perf-record.txt |   3 +
 tools/perf/Documentation/perf-stat.txt   |   3 +
 tools/perf/Makefile.perf                 |   2 +
 tools/perf/builtin-list.c                |   2 +
 tools/perf/builtin-record.c              |   3 +
 tools/perf/builtin-stat.c                |   2 +
 tools/perf/util/jevents.c                | 248 +++++++++++++++++++++++++++++++
 tools/perf/util/jevents.h                |   3 +
 tools/perf/util/pmu.c                    |  14 ++
 tools/perf/util/pmu.h                    |   2 +
 11 files changed, 288 insertions(+)
 create mode 100644 tools/perf/util/jevents.c
 create mode 100644 tools/perf/util/jevents.h

tools/perf/Documentation/perf-list.txt +0 -0

index 6fce6a6..d399e04 100644

tools/perf/Documentation/perf-list.txt +3 -0

+Specify JSON event list file to use for parsing events.
+
+
 [[EVENT_MODIFIERS]]
 EVENT MODIFIERS
 ---------------

tools/perf/Documentation/perf-record.txt +3 -0

index c71b0f3..8a1e0d9 100644
@@ -213,6 +213,9 @@ if combined with -a or -C options.
 After starting the program, wait msecs before measuring. This is useful to
 filter out the startup phase of the program, which is often very different.
 
+--json-file=::
+Specify JSON event list file to use for parsing events.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1], linkperf:perf-list[1]

tools/perf/Documentation/perf-stat.txt +3 -0

index 29ee857..a946283 100644
@@ -142,6 +142,9 @@ filter out the startup phase of the program, which is often very different.
 
 Print statistics of transactional execution if supported.
 
+--json-file=::
+Specify JSON event list file to use for parsing events.
+
 EXAMPLES
 --------
 

tools/perf/Makefile.perf +2 -0

index 43d4109..8800838 100644
@@ -302,6 +302,7 @@ LIB_H += ui/ui.h
 LIB_H += util/data.h
 LIB_H += util/jsmn.h
 LIB_H += util/json.h
+LIB_H += util/jevents.h
 
 LIB_OBJS += $(OUTPUT)util/abspath.o
 LIB_OBJS += $(OUTPUT)util/alias.o

@@ -377,6 +378,7 @@ LIB_OBJS += $(OUTPUT)util/srcline.o
 LIB_OBJS += $(OUTPUT)util/data.o
 LIB_OBJS += $(OUTPUT)util/jsmn.o
 LIB_OBJS += $(OUTPUT)util/json.o
+LIB_OBJS += $(OUTPUT)util/jevents.o
 
 LIB_OBJS += $(OUTPUT)ui/setup.o
 LIB_OBJS += $(OUTPUT)ui/helpline.o

tools/perf/builtin-list.c +2 -0

index 011195e..ca3dd18 100644
@@ -20,6 +20,8 @@ int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	int i;
 	const struct option list_options[] = {
+		OPT_STRING(0, "json-file", &json_file, "json file",
+			   "Read event json file"),
 		OPT_END()
 	};
 	const char * const list_usage[] = {

tools/perf/builtin-record.c +3 -0

index e4c85b8..e4a5be0 100644
@@ -25,6 +25,7 @@
 #include "util/cpumap.h"
 #include "util/thread_map.h"
 #include "util/data.h"
+#include "util/pmu.h"
 
 #include <unistd.h>
 #include <sched.h>

@@ -871,6 +872,8 @@ const struct option record_options[] = {
 		    "sample transaction flags (special events only)"),
 	OPT_BOOLEAN(0, "per-thread", &record.opts.target.per_thread,
 		    "use per-thread mmaps"),
+	OPT_STRING(0, "json-file", &json_file, "json file",
+		   "Read event json file"),
 	OPT_END()
 };
 

tools/perf/builtin-stat.c +2 -0

index 65a151e..461ff0a 100644
@@ -1668,6 +1668,8 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
 		     "aggregate counts per physical processor core", AGGR_CORE),
 	OPT_UINTEGER('D', "delay", &initial_delay,
 		     "ms to wait before starting measurement after program start"),
+	OPT_STRING(0, "json-file", &json_file, "json file",
+		   "Read event json file"),
 	OPT_END()
 	};
 	const char * const stat_usage[] = {

tools/perf/util/jevents.c new file +39 -0

new file mode 100644
index 0000000..0173b68
@@ -0,0 +1,248 @@
+/* Parse event JSON files */
+
+/*
+ * Copyright (c) 2014, Intel Corporation
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <ctype.h>
+#include "jsmn.h"
+#include "json.h"
+#include "jevents.h"
+

tools/perf/util/jevents.c new file +33 -0

+	if (!olen)
+		*(*dst) = 0;
+	else
+		strcat(*dst, sep);
+	strcat(*dst, a);
+	if (bt)
+		strncat(*dst, map + bt->start, blen);
+}
+
+static void fixname(char *s)
+{
+	for (; *s; s++) {
+		*s = tolower(*s);
+		/*
+		 * Remove '.' for now, until the parser
+		 * can deal with it.
+		 */
+		if (*s == '.')
+			*s = '_';
+	}
+}
+
+static void fixdesc(char *s)
+{
+	char *e = s + strlen(s);
+
+	/* Remove trailing dots that look ugly in perf list */
+	--e;
+	while (e >= s && isspace(*e))
+		--e;
+	if (*e == '.')
+		*e = 0;
+}

tools/perf/util/jevents.c new file +105 -0

+
+static struct msrmap {
+	const char *num;
+	const char *pname;
+} msrmap[] = {
+	{ "0x3F6", "ldlat=" },
+	{ "0x1A6", "offcore_rsp=" },
+	{ "0x1A7", "offcore_rsp=" },
+	{ NULL, NULL }
+};
+
+static struct field {
+	const char *field;
+	const char *kernel;
+} fields[] = {
+	{ "EventCode",	"event=" },
+	{ "UMask",	"umask=" },
+	{ "CounterMask", "cmask=" },
+	{ "Invert",	"inv=" },
+	{ "AnyThread",	"any=" },
+	{ "EdgeDetect",	"edge=" },
+	{ "SampleAfterValue", "period=" },
+	{ NULL, NULL }
+};
+
+static void cut_comma(char *map, jsmntok_t *newval)
+{
+	int i;
+
+	/* Cut off everything after comma */
+	for (i = newval->start; i < newval->end; i++) {
+		if (map[i] == ',')
+			newval->end = i;
+	}
+}
+
+static int match_field(char *map, jsmntok_t *field, int nz,
+		       char **event, jsmntok_t *val)
+{
+	struct field *f;
+	jsmntok_t newval = *val;
+
+	for (f = fields; f->field; f++)
+		if (json_streq(map, field, f->field) && nz) {
+			cut_comma(map, &newval);
+			addfield(map, event, ",", f->kernel, &newval);
+			return 1;
+		}
+	return 0;
+}
+
+static struct msrmap *lookup_msr(char *map, jsmntok_t *val)
+{
+	jsmntok_t newval = *val;
+	static bool warned;
+	int i;
+
+	cut_comma(map, &newval);
+	for (i = 0; msrmap[i].num; i++)
+		if (json_streq(map, &newval, msrmap[i].num))
+			return &msrmap[i];
+	if (!warned) {
+		warned = true;
+		pr_err("Unknown MSR in event file %.*s\n",
+			json_len(val), map + val->start);
+	}
+	return NULL;
+}
+
+/* Call func with each event in the json file */
+
+int json_events(const char *fn,
+	  int (*func)(void *data, char *name, char *event, char *desc),
+	  void *data)
+{
+	int err = -EIO;
+	size_t size;
+	jsmntok_t *tokens, *tok;
+	int i, j, len;
+	char *map;
+
+	tokens = parse_json(fn, &map, &size, &len);
+	if (!tokens)
+		return -EIO;
+	EXPECT(tokens->type == JSMN_ARRAY, tokens, "expected top level array");
+	tok = tokens + 1;
+	for (i = 0; i < tokens->size; i++) {
+		char *event = NULL, *desc = NULL, *name = NULL;
+		struct msrmap *msr = NULL;
+		jsmntok_t *msrval = NULL;
+		jsmntok_t *precise = NULL;
+		jsmntok_t *obj = tok++;
+
+		EXPECT(obj->type == JSMN_OBJECT, obj, "expected object");
+		for (j = 0; j < obj->size; j += 2) {
+			jsmntok_t *field, *val;
+			int nz;
+
+			field = tok + j;
+			EXPECT(field->type == JSMN_STRING, tok + j,
+			       "Expected field name");
+			val = tok + j + 1;
+			EXPECT(val->type == JSMN_STRING, tok + j + 1,
+			       "Expected string value");
+

tools/perf/util/jevents.c new file +41 -0

+				precise = val;
+			} else if (json_streq(map, field, "MSRIndex") && nz) {
+				msr = lookup_msr(map, val);
+			} else if (json_streq(map, field, "MSRValue")) {
+				msrval = val;
+			} else if (json_streq(map, field, "Errata") &&
+				   !json_streq(map, val, "null")) {
+				addfield(map, &desc, ". ",
+					" Spec update: ", val);
+			} else if (json_streq(map, field, "Data_LA") && nz) {
+				addfield(map, &desc, ". ",
+					" Supports address when precise",
+					NULL);
+			}
+			/* ignore unknown fields */
+		}
+		if (precise) {
+			if (json_streq(map, precise, "2"))
+				addfield(map, &desc, " ", "(Must be precise)",
+						NULL);
+			else
+				addfield(map, &desc, " ",
+						"(Precise event)", NULL);
+		}
+		if (msr != NULL)
+			addfield(map, &event, ",", msr->pname, msrval);
+		fixname(name);
+		err = func(data, name, event, desc);
+		free(event);
+		free(desc);
+		free(name);
+		if (err)
+			break;
+		tok += j;
+	}
+	EXPECT(tok - tokens == len, tok, "unexpected objects at end");
+	err = 0;
+out_free:
+	free_json(map, size, tokens);
+	return err;
+}

tools/perf/util/jevents.h new file +3 -0

new file mode 100644
index 0000000..4c2b879
@@ -0,0 +1,3 @@
+int json_events(const char *fn,
+		int (*func)(void *data, char *name, char *event, char *desc),
+		void *data);

tools/perf/util/pmu.c +14 -0

index baec090..9f154af 100644
@@ -9,6 +9,9 @@
 #include "pmu.h"
 #include "parse-events.h"
 #include "cpumap.h"
+#include "jevents.h"
+
+const char *json_file;
 
 #define UNIT_MAX_LEN	31 /* max length for event unit name */
 

@@ -273,6 +276,14 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
 	return ret;
 }
 
+static int add_alias(void *data, char *name, char *event, char *desc)
+{
+	struct list_head *head = (struct list_head *)data;
+
+	__perf_pmu__new_alias(head, name, NULL, desc, event);
+	return 0;
+}
+
 /*
  * Reading the pmu event aliases definition, which should be located at:
  * /sys/bus/event_source/devices/<dev>/events as sysfs group attributes.

@@ -422,6 +433,9 @@ static struct perf_pmu *pmu_lookup(const char *name)
 	if (pmu_aliases(name, &aliases))
 		return NULL;
 
+	if (!strcmp(name, "cpu") && json_file)
+		json_events(json_file, add_alias, &aliases);
+
 	if (pmu_type(name, &type))
 		return NULL;
 

tools/perf/util/pmu.h +2 -0

index c14a543..583d21e 100644
@@ -46,4 +46,6 @@ void print_pmu_events(const char *event_glob, bool name_only);
 bool pmu_have_event(const char *pname, const char *name);
 
 int perf_pmu__test(void);
+
+extern const char *json_file;
 #endif /* __PMU_H */

And more generally, can we extend these if-else's to a generic loop to check a table like in match_field() so that it can be added easily?

From: Andi Kleen <[email protected]>

Add a downloader to automatically download the right files from a download site.

This is implemented as a script calling wget, similar to perf archive. The perf driver automatically calls the right binary. The downloader is extensible, but currently only implements an Intel event download. It would be straightforward to add other sites too for other vendors.

The downloaded event files are put into ~/.cache/pmu-events, where the builtin event parser in util/* can find them automatically.

Cc Use ~/.cache

tools/perf/perf-download.sh new file +40 -0

+END	      { printf("%s-%s-%X", V, F, M) }' /proc/cpuinfo)
+else
+	S="$1"
+fi
+V=$(echo $S  | ( IFS=- read v f m ; echo $v) )
+
+CACHEDIR=${XDG_CACHE_HOME:-~/.cache}
+[ ! -d $CACHEDIR/pmu-events ] && mkdir -p $CACHEDIR/pmu-events
+cd $CACHEDIR/pmu-events
+
+case "$V" in
+GenuineIntel)
+	echo "Downloading models file"
+	URLBASE=${URLBASE:-https://download.01.org/perfmon}
+	MAPFILE=${MAPFILE:-mapfile.csv}
+	echo "Downloading readme.txt"
+	wget -N $WGETOPT $URLBASE/readme.txt
+	;;
+
+# Add more CPU vendors here
+
+*)
+	echo "Unsupported CPU vendor $V"
+	exit 1
+	;;
+esac
+
+wget -N $WGETOPT $URLBASE/$MAPFILE
+
+echo "Downloading events file"
+awk -v urlbase=$URLBASE -v cpu="$S" -F, \
+	'$1 == cpu && $4 == "core" { print urlbase $3; exit 0 }' \
+	$MAPFILE > url$$
+if [ -s url$$ ] ; then
+	wget $WGETOPT -q -i url$$ -O $S-core.json
+else
+	echo "CPU $S not found"
+fi
+rm -f url$$
+

Could you please extend this script to support curl also? It seems the wget is not installed by default on my system.

tools/perf/perf-download.sh line 12

Quoted 7 lines

tools/perf/perf-download.sh new file +7 -0

+set -e
+
+if [ "$1" == "" ] ; then
+	S=$(awk '
+/^vendor/     		{ V=$3 }
+/^model/ && $2 == ":" 	{ M=$3 }
+/^cpu family/ 		{ F = $4 }

Inconsistency in using whitespace..

+int test__aliases(void)

tools/perf/tests/aliases.c new file +9 -0

+{
+	int err;
+
+	/* Download JSON files */
+	/* XXX assumes perf is installed */
+	/* For now user must manually download */
+	if (0 && system("perf download > /dev/null") < 0) {
+		/* Don't error out for this for now */
+		fprintf(stderr, "perf download failed\n");

tools/perf/tests/aliases.c new file +3 -0

+	perf_evlist__delete(evlist);
+	return err;
+}

From: Andi Kleen <[email protected]>

Fix the logic to allow overriding event default periods with -c or -F on the command line. I'm not sure I understand this if() fully, but this change makes all cases I tested work (tracepoint with default, default, ,-c, -F)

This fixed specifying -c / -F with json event list events, which have a default period. It should do the same for trace point events.

Quoted 7 lines · Andi Kleen

From: Andi Kleen <[email protected]>

Fix the logic to allow overriding event default periods with -c or -F on the command line. I'm not sure I understand this if() fully, but this change makes all cases I tested work (tracepoint with default, default, ,-c, -F)

Quoted 3 lines

This fixed specifying -c / -F with json event list events, which have a default period. It should do the same for trace point events.

Hmm.. doesn't that require both -c and -F are given at the same time?

Anyway, there was a similar discussion, but I suggested an other way. Please see the line below.

I implemented an automatic downloader to get the event file for the current CPU. The events are stored in ~/.events.
Then perf adds a parser that converts the JSON format into perf event aliases, which then can be used directly as any other perf event.

Quoted 4 lines · Andi Kleen

I implemented an automatic downloader to get the event file for the current CPU. The events are stored in ~/.events.
Then perf adds a parser that converts the JSON format into perf event aliases, which then can be used directly as any other perf event.

Should the name of the file not more specific? I mean .events can mean everything? Every program may have a demand for this generic name. Why not ~/.perf-events? Even more standard [1]:
$XDG_CACHE_HOME/perf/events (i.e. ~/.cache/perf/events)