Re: [PATCH 9/9] perf tool: Add pmu event alias support

Yan, Zheng
2012-05-07T08:34:21Z

On 05/04/2012 04:05 AM, Jiri Olsa wrote:
> On Thu, May 03, 2012 at 01:24:21PM +0200, Peter Zijlstra wrote:
>> On Thu, 2012-05-03 at 12:56 +0200, Jiri Olsa wrote:
>>> - in sysfs you would have directory with aliases (now called 'events')
>>> - each alias is sysfs dir, with file attrs:
>>> file name = term name, file value = term value
>>> eg.:
>>> events/
>>> CAS_COUNT_RD/
>>> # files:
>>> config - value 1
>>> config1 - value 2
>>> mask - value ...
>>
>> I'd prefer the thing Yan proposed (if the sysfs folks let us),
>>
>> $foo/events/QHL_REQUEST_REMOTE_READS
>>
>> with contents: "event=0x20,umask=0x4"
>>
>>> this way it's also possible to add extra terms to existing alias
>>> in command line if needed... might be handy
>>>
>> That should always be possible, if you modify the parser to take things
>> like:
>>
>> event=0x20,umask=0x4,event=0x21
>>
>> and have latter values override earlier values, so it collapses into:
>>
>> umask=0x4,event=0x21
>>
>> you can simply take whatever comes out of the event file and stick extra
>> bits at the end.
>
> I discussed this with Peter on irc, so I'll try to sum it up
>
> we have following options so far:
>
> with event alias 'al' with definition 'config=1,config1=1,config2=2'
>
> 1) inside parse_events_add_pmu function
> once alias term is detected as part of event definition 'pmu/al/mod' we
> construct new event 'pmu/config=1,config1=1,config2=2/mod' and rerun the
> event parser on that
>
> 2) inside parse_events_add_pmu function
> once alias term is detected as part of event definition 'pmu/al/mod' we
> replace that term with list of terms for that alias definition and run
> perf_pmu__config with this new term list
>
> 3) during bison/flex processing
> have option 2) embeded inside flex/bison rules. Once alias term
> is detected, insert the aliased terms directly to the list of terms,
> not replacing expos as in option 2.
>
>
> - option 1 is currently implemented
> - options 2 and 3 requires the aliased config is loaded/parsed from pmu
> sysfs tree in form of terms list
> - option 3 is a little fuzzy for me now on how to integrate this with
> flex/bison
>
> My interest here is to go with option 2 or 3 if possible - preferrably 2 ;),
> because I think it's better/cleaner to deal with terms in one place once they
> are parsed - in parse_events_add_pmu function.
>
> I think there's no need to re run the whole parser (option 1) when we
> have the whole thing ready by adding just extra terms.
>
> thoughts?
>

How is the patch below, it implements option 2.

Thanks
---
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index c587ae8..4ed4278 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -656,22 +656,33 @@ int parse_events_add_pmu(struct list_head *list, int *idx,
struct perf_event_attr attr;
struct perf_pmu *pmu;

+ /* called by parse_event_config? */
+ if (!idx) {
+ list_splice_init(head_config, list);
+ return 0;
+ }
+
pmu = perf_pmu__find(name);
if (!pmu)
return -EINVAL;

memset(&attr, 0, sizeof(attr));

- /*
- * Configure hardcoded terms first, no need to check
- * return value when called with fail == 0 ;)
- */
- config_attr(&attr, head_config, 0);
+ while (1) {
+ /*
+ * Configure hardcoded terms first, no need to check
+ * return value when called with fail == 0 ;)
+ */
+ config_attr(&attr, head_config, 0);

- if (perf_pmu__config(pmu, &attr, head_config))
- return -EINVAL;
+ if (!perf_pmu__config(pmu, &attr, head_config))
+ return add_event(list, idx, &attr, (char *) "pmu");

- return add_event(list, idx, &attr, (char *) "pmu");
+ head_config = perf_pmu__alias(pmu, head_config);
+ if (!head_config)
+ break;
+ }
+ return -EINVAL;
}

void parse_events_update_lists(struct list_head *list_event,
@@ -771,6 +782,26 @@ static int __parse_events(const char *str, int *idx, struct list_head *list)
return ret;
}

+/*
+ * parse event config string, return a list of event terms.
+ */
+int parse_event_config(struct list_head *terms, const char *str)
+{
+ char *buf;
+ int ret;
+
+ buf = malloc(strlen(str) + 6);
+ if (!buf)
+ return -ENOMEM;
+
+ /* It is no matter which pmu is used here */
+ sprintf(buf, "cpu/%s/", str);
+ ret = __parse_events(buf, NULL, terms);
+
+ free(buf);
+ return ret;
+}
+
int parse_events(struct perf_evlist *evlist, const char *str, int unset __used)
{
LIST_HEAD(list);
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index e1ffeb7..5b5d698 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -30,6 +30,7 @@ extern int parse_events_option(const struct option *opt, const char *str,
extern int parse_events(struct perf_evlist *evlist, const char *str,
int unset);
extern int parse_filter(const struct option *opt, const char *str, int unset);
+extern int parse_event_config(struct list_head *terms, const char *str);

#define EVENTS_HELP_MAX (128*1024)

diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 52082a7..8a26f3d 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -197,7 +197,7 @@ PE_NAME
{
struct parse_events__term *term;

- ABORT_ON(parse_events__new_term(&term, PARSE_EVENTS__TERM_TYPE_NUM,
+ ABORT_ON(parse_events__new_term(&term, PARSE_EVENTS__TERM_TYPE_STR,
$1, NULL, 1));
$$ = term;
}
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index cb08a11..7a85779 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -80,6 +80,95 @@ static int pmu_format(char *name, struct list_head *format)
return 0;
}

+static int perf_pmu__new_alias(struct list_head *list, char *name, FILE *file)
+{
+ struct perf_pmu__alias *alias;
+ char buf[256];
+ int ret;
+
+ ret = fread(buf, 1, sizeof(buf), file);
+ if (ret == 0)
+ return -EINVAL;
+ buf[ret] = 0;
+
+ alias = malloc(sizeof(*alias));
+ if (!alias)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&alias->terms);
+ ret = parse_event_config(&alias->terms, buf);
+ if (ret) {
+ free(alias);
+ return ret;
+ }
+
+ alias->name = strdup(name);
+ list_add_tail(&alias->list, list);
+ return 0;
+}
+
+/*
+ * Process all the sysfs attributes located under the directory
+ * specified in 'dir' parameter.
+ */
+static int pmu_aliases_parse(char *dir, struct list_head *head)
+{
+ struct dirent *evt_ent;
+ DIR *event_dir;
+ int ret = 0;
+
+ event_dir = opendir(dir);
+ if (!event_dir)
+ return -EINVAL;
+
+ while (!ret && (evt_ent = readdir(event_dir))) {
+ char path[PATH_MAX];
+ char *name = evt_ent->d_name;
+ FILE *file;
+
+ if (!strcmp(name, ".") || !strcmp(name, ".."))
+ continue;
+
+ snprintf(path, PATH_MAX, "%s/%s", dir, name);
+
+ ret = -EINVAL;
+ file = fopen(path, "r");
+ if (!file)
+ break;
+ ret = perf_pmu__new_alias(head, name, file);
+ fclose(file);
+ }
+
+ closedir(event_dir);
+ return ret;
+}
+
+/*
+ * Reading the pmu event aliases definition, which should be located at:
+ * /sys/bus/event_source/devices/<dev>/events as sysfs group attributes.
+ */
+static int pmu_aliases(char *name, struct list_head *head)
+{
+ struct stat st;
+ char path[PATH_MAX];
+ const char *sysfs;
+
+ sysfs = sysfs_find_mountpoint();
+ if (!sysfs)
+ return -1;
+
+ snprintf(path, PATH_MAX,
+ "%s/bus/event_source/devices/%s/events", sysfs, name);
+
+ if (stat(path, &st) < 0)
+ return -1;
+
+ if (pmu_aliases_parse(path, head))
+ return -1;
+
+ return 0;
+}
+
/*
* Reading/parsing the default pmu type value, which should be
* located at:
@@ -118,6 +207,7 @@ static struct perf_pmu *pmu_lookup(char *name)
{
struct perf_pmu *pmu;
LIST_HEAD(format);
+ LIST_HEAD(aliases);
__u32 type;

/*
@@ -135,8 +225,12 @@ static struct perf_pmu *pmu_lookup(char *name)
if (!pmu)
return NULL;

+ pmu_aliases(name, &aliases);
+
INIT_LIST_HEAD(&pmu->format);
+ INIT_LIST_HEAD(&pmu->aliases);
list_splice(&format, &pmu->format);
+ list_splice(&aliases, &pmu->aliases);
pmu->name = strdup(name);
pmu->type = type;
return pmu;
@@ -262,6 +356,35 @@ static int pmu_config(struct list_head *formats, struct perf_event_attr *attr,
return 0;
}

+static struct perf_pmu__alias *pmu_find_alias(struct list_head *events,
+ char *name)
+{
+ struct perf_pmu__alias *alias;
+
+ list_for_each_entry(alias, events, list) {
+ if (!strcmp(alias->name, name))
+ return alias;
+ }
+ return NULL;
+}
+
+struct list_head *perf_pmu__alias(struct perf_pmu *pmu,
+ struct list_head *head_terms)
+{
+ struct parse_events__term *term;
+ struct perf_pmu__alias *alias;
+
+ if (!list_is_singular(head_terms))
+ return NULL;
+
+ term = list_entry(head_terms->next, struct parse_events__term, list);
+ if (term->type != PARSE_EVENTS__TERM_TYPE_STR || term->val.str)
+ return NULL;
+
+ alias = pmu_find_alias(&pmu->aliases, term->config);
+ return &alias->terms;
+}
+
/*
* Configures event's 'attr' parameter based on the:
* 1) users input - specified in terms parameter
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 68c0db9..8fad317 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -19,17 +19,25 @@ struct perf_pmu__format {
struct list_head list;
};

+struct perf_pmu__alias {
+ char *name;
+ struct list_head terms;
+ struct list_head list;
+};
+
struct perf_pmu {
char *name;
__u32 type;
struct list_head format;
+ struct list_head aliases;
struct list_head list;
};

struct perf_pmu *perf_pmu__find(char *name);
int perf_pmu__config(struct perf_pmu *pmu, struct perf_event_attr *attr,
struct list_head *head_terms);
-
+struct list_head *perf_pmu__alias(struct perf_pmu *pmu,
+ struct list_head *head_terms);
int perf_pmu_wrap(void);
void perf_pmu_error(struct list_head *list, char *name, char const *msg);