* [Question] perf tools: lex parsing issue
@ 2021-08-23 11:27 John Garry
2021-08-25 0:13 ` Ian Rogers
0 siblings, 1 reply; 5+ messages in thread
From: John Garry @ 2021-08-23 11:27 UTC (permalink / raw)
To: Jiri Olsa, Arnaldo Carvalho de Melo
Cc: linux-kernel, linux-perf-users, Peter Zijlstra, irogers,
Ingo Molnar, Mark Rutland, Alexander Shishkin, Namhyung Kim
Hi jirka,
If you remember from some time ago we discussed how the lex parsing
creates strange aliases:
https://lore.kernel.org/lkml/20200320093006.GA1343171@krava/
I am no expert on l+y, but it seems that we simply don't set the term
config field for known term types. Well, not for
PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD type anyway.
This super hack resolves that issue:
--->8----
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -765,7 +765,12 @@ event_config ',' event_term
struct list_head *head = $1;
struct parse_events_term *term = $3
+ if (term->type_term == PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD) {
+ term->config = strdup("period");
+ }
+
if (!head) {
parse_events_term__delete(term);
YYABORT;
--
----8-----
So we get "umask=0x80,period=0x30d40,event=0x6" now, rather than
"umask=0x80,(null)=0x30d40,event=0x6", for the perf_pmu_alias.str, as an
example.
Did you ever get a chance to look into this issue? Do you know how could
or should this field be set properly?
Some more background:
The reason I was looking at this is because I think it causes a problem
for pmu-events (JSONs) aliasing for some PMUs. Specifically it's PMU
which use "config=xxx" in sysfs files in
/sys/bus/event_source/devices/PMUx/events/, rather than "event=xxx". The
actual problem is that I trigger this warn in pmu.c:
static void perf_pmu_assign_str(char *name, const char *field, char
**old_str,
char **new_str)
{
if (*new_str) { /* Have new string, check with old */
if (strcasecmp(*old_str, *new_str))
pr_debug("alias %s differs i ... <---
As I get "config=event=0xXXX" vs "config=(null)=0xXXX"
As I am not sure how to solve that yet, but, since we have
config=(null), I thought it best to solve the first issue first.
Thanks,
John
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Question] perf tools: lex parsing issue
2021-08-23 11:27 [Question] perf tools: lex parsing issue John Garry
@ 2021-08-25 0:13 ` Ian Rogers
2021-08-25 14:36 ` John Garry
0 siblings, 1 reply; 5+ messages in thread
From: Ian Rogers @ 2021-08-25 0:13 UTC (permalink / raw)
To: John Garry
Cc: Jiri Olsa, Arnaldo Carvalho de Melo, linux-kernel,
linux-perf-users, Peter Zijlstra, Ingo Molnar, Mark Rutland,
Alexander Shishkin, Namhyung Kim
On Mon, Aug 23, 2021 at 4:23 AM John Garry <john.garry@huawei.com> wrote:
>
> Hi jirka,
>
> If you remember from some time ago we discussed how the lex parsing
> creates strange aliases:
>
> https://lore.kernel.org/lkml/20200320093006.GA1343171@krava/
>
> I am no expert on l+y, but it seems that we simply don't set the term
> config field for known term types. Well, not for
> PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD type anyway.
>
> This super hack resolves that issue:
>
> --->8----
>
> --- a/tools/perf/util/parse-events.y
> +++ b/tools/perf/util/parse-events.y
> @@ -765,7 +765,12 @@ event_config ',' event_term
> struct list_head *head = $1;
> struct parse_events_term *term = $3
>
> + if (term->type_term == PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD) {
> + term->config = strdup("period");
> + }
> +
> if (!head) {
> parse_events_term__delete(term);
> YYABORT;
> --
>
> ----8-----
Agreed this is hacky, I think it'd be better to fix this up in the
output. For example:
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 6cdbee8a12e7..c77c42275efa 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -365,15 +365,21 @@ static int __perf_pmu__new_alias(struct
list_head *list, char *dir, char *name,
memset(newval, 0, sizeof(newval));
ret = 0;
list_for_each_entry(term, &alias->terms, list) {
+ const char * config = term->config;
+
if (ret)
ret += scnprintf(newval + ret, sizeof(newval) - ret,
",");
+ if (!config) {
+ /* Note: config_term_names in parse_events.c
isn't accessible */
+ config = config_term_names[term->type_term];
+ }
if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
ret += scnprintf(newval + ret, sizeof(newval) - ret,
- "%s=%#x", term->config, term->val.num);
+ "%s=%#x", config, term->val.num);
else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
ret += scnprintf(newval + ret, sizeof(newval) - ret,
- "%s=%s", term->config, term->val.str);
+ "%s=%s", config, term->val.str);
}
alias->name = strdup(name);
It looks like a similar fix is needed in format_alias.
Thanks,
Ian
> So we get "umask=0x80,period=0x30d40,event=0x6" now, rather than
> "umask=0x80,(null)=0x30d40,event=0x6", for the perf_pmu_alias.str, as an
> example.
>
> Did you ever get a chance to look into this issue? Do you know how could
> or should this field be set properly?
>
> Some more background:
> The reason I was looking at this is because I think it causes a problem
> for pmu-events (JSONs) aliasing for some PMUs. Specifically it's PMU
> which use "config=xxx" in sysfs files in
> /sys/bus/event_source/devices/PMUx/events/, rather than "event=xxx". The
> actual problem is that I trigger this warn in pmu.c:
>
> static void perf_pmu_assign_str(char *name, const char *field, char
> **old_str,
> char **new_str)
> {
>
> if (*new_str) { /* Have new string, check with old */
> if (strcasecmp(*old_str, *new_str))
> pr_debug("alias %s differs i ... <---
>
> As I get "config=event=0xXXX" vs "config=(null)=0xXXX"
>
> As I am not sure how to solve that yet, but, since we have
> config=(null), I thought it best to solve the first issue first.
>
> Thanks,
> John
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [Question] perf tools: lex parsing issue
2021-08-25 0:13 ` Ian Rogers
@ 2021-08-25 14:36 ` John Garry
2021-08-25 16:47 ` Ian Rogers
0 siblings, 1 reply; 5+ messages in thread
From: John Garry @ 2021-08-25 14:36 UTC (permalink / raw)
To: Ian Rogers
Cc: Jiri Olsa, Arnaldo Carvalho de Melo, linux-kernel,
linux-perf-users, Peter Zijlstra, Ingo Molnar, Mark Rutland,
Alexander Shishkin, Namhyung Kim
On 25/08/2021 01:13, Ian Rogers wrote:
Thanks for getting back to me
>> + if (term->type_term == PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD) {
>> + term->config = strdup("period");
>> + }
>> +
>> if (!head) {
>> parse_events_term__delete(term);
>> YYABORT;
>> --
>>
>> ----8-----
> Agreed this is hacky,
This might be a *bit* better:
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index e5eae23cfceb..e597beaaa179 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1058,6 +1058,13 @@ static const char
*config_term_names[__PARSE_EVENTS__TERM_TYPE_NR] = {
[PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE] = "aux-sample-size",
};
+const char * get_config_term(int term_type)
+{
+ if (term_type >= __PARSE_EVENTS__TERM_TYPE_NR)
+ return "";
+ return config_term_names[term_type];
+}
+
static bool config_term_shrinked;
static bool
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index bf6e41aa9b6a..0f658732535f 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -90,6 +90,8 @@ enum {
__PARSE_EVENTS__TERM_TYPE_NR,
};
+const char *get_config_term(int term_type);
+
struct parse_events_array {
size_t nr_ranges;
struct {
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 9321bd0e2f76..8d6d3fae226d 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -832,8 +832,9 @@ PE_TERM '=' PE_NAME
PE_TERM '=' PE_VALUE
{
struct parse_events_term *term;
+ char *config = strdup(get_config_term($1));
- ABORT_ON(parse_events_term__num(&term, (int)$1, NULL, $3, false, &@1,
&@3));
+ ABORT_ON(parse_events_term__num(&term, (int)$1, config, $3, false,
&@1, &@3));
$$ = term;
}
> I think it'd be better to fix this up in the
> output. For example:
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 6cdbee8a12e7..c77c42275efa 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -365,15 +365,21 @@ static int __perf_pmu__new_alias(struct
> list_head *list, char *dir, char *name,
> memset(newval, 0, sizeof(newval));
> ret = 0;
> list_for_each_entry(term, &alias->terms, list) {
> + const char * config = term->config;
> +
> if (ret)
> ret += scnprintf(newval + ret, sizeof(newval) - ret,
> ",");
> + if (!config) {
> + /* Note: config_term_names in parse_events.c
> isn't accessible */
> + config = config_term_names[term->type_term];
We could just expose some parse-events.c API, like above.
> + }
> if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
> ret += scnprintf(newval + ret, sizeof(newval) - ret,
> - "%s=%#x", term->config, term->val.num);
> + "%s=%#x", config, term->val.num);
> else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
> ret += scnprintf(newval + ret, sizeof(newval) - ret,
> - "%s=%s", term->config, term->val.str);
> + "%s=%s", config, term->val.str);
> }
>
> alias->name = strdup(name);
But how about this alternative simple one:
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index e5eae23cfceb..9e5df934d22d 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -3084,7 +3084,7 @@ int parse_events_term__num(struct
parse_events_term **term,
struct parse_events_term temp = {
.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
.type_term = type_term,
- .config = config,
+ .config = config ? : strdup(config_term_names[type_term]),
.no_value = no_value,
.err_term = loc_term ? loc_term->first_column : 0,
.err_val = loc_val ? loc_val->first_column : 0,
--
>
> It looks like a similar fix is needed in format_alias.
And the change in parse_events_term__num(), above, seems to resolve that.
Previously we would have something like these in format_alias():
buf=i915/bcs0-busy, pmu name=i915, alias->name=bcs0-busy ->str=(null)=0x1000
And now:
buf=i915/bcs0-busy, pmu name=i915, alias->name=bcs0-busy ->str=config=0x1000
Thoughts?
Thanks,
John
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [Question] perf tools: lex parsing issue
2021-08-25 14:36 ` John Garry
@ 2021-08-25 16:47 ` Ian Rogers
2021-08-25 16:58 ` John Garry
0 siblings, 1 reply; 5+ messages in thread
From: Ian Rogers @ 2021-08-25 16:47 UTC (permalink / raw)
To: John Garry
Cc: Jiri Olsa, Arnaldo Carvalho de Melo, linux-kernel,
linux-perf-users, Peter Zijlstra, Ingo Molnar, Mark Rutland,
Alexander Shishkin, Namhyung Kim
On Wed, Aug 25, 2021 at 7:32 AM John Garry <john.garry@huawei.com> wrote:
>
> On 25/08/2021 01:13, Ian Rogers wrote:
>
> Thanks for getting back to me
>
>
> >> + if (term->type_term == PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD) {
> >> + term->config = strdup("period");
> >> + }
> >> +
> >> if (!head) {
> >> parse_events_term__delete(term);
> >> YYABORT;
> >> --
> >>
> >> ----8-----
> > Agreed this is hacky,
>
> This might be a *bit* better:
>
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index e5eae23cfceb..e597beaaa179 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -1058,6 +1058,13 @@ static const char
> *config_term_names[__PARSE_EVENTS__TERM_TYPE_NR] = {
> [PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE] = "aux-sample-size",
> };
>
> +const char * get_config_term(int term_type)
> +{
> + if (term_type >= __PARSE_EVENTS__TERM_TYPE_NR)
> + return "";
> + return config_term_names[term_type];
> +}
> +
> static bool config_term_shrinked;
>
> static bool
> diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
> index bf6e41aa9b6a..0f658732535f 100644
> --- a/tools/perf/util/parse-events.h
> +++ b/tools/perf/util/parse-events.h
> @@ -90,6 +90,8 @@ enum {
> __PARSE_EVENTS__TERM_TYPE_NR,
> };
>
> +const char *get_config_term(int term_type);
> +
> struct parse_events_array {
> size_t nr_ranges;
> struct {
> diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
> index 9321bd0e2f76..8d6d3fae226d 100644
> --- a/tools/perf/util/parse-events.y
> +++ b/tools/perf/util/parse-events.y
> @@ -832,8 +832,9 @@ PE_TERM '=' PE_NAME
> PE_TERM '=' PE_VALUE
> {
> struct parse_events_term *term;
> + char *config = strdup(get_config_term($1));
>
> - ABORT_ON(parse_events_term__num(&term, (int)$1, NULL, $3, false, &@1,
> &@3));
> + ABORT_ON(parse_events_term__num(&term, (int)$1, config, $3, false,
> &@1, &@3));
> $$ = term;
> }
>
>
> > I think it'd be better to fix this up in the
> > output. For example:
> >
> > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> > index 6cdbee8a12e7..c77c42275efa 100644
> > --- a/tools/perf/util/pmu.c
> > +++ b/tools/perf/util/pmu.c
> > @@ -365,15 +365,21 @@ static int __perf_pmu__new_alias(struct
> > list_head *list, char *dir, char *name,
> > memset(newval, 0, sizeof(newval));
> > ret = 0;
> > list_for_each_entry(term, &alias->terms, list) {
> > + const char * config = term->config;
> > +
> > if (ret)
> > ret += scnprintf(newval + ret, sizeof(newval) - ret,
> > ",");
> > + if (!config) {
> > + /* Note: config_term_names in parse_events.c
> > isn't accessible */
> > + config = config_term_names[term->type_term];
>
> We could just expose some parse-events.c API, like above.
>
> > + }
> > if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
> > ret += scnprintf(newval + ret, sizeof(newval) - ret,
> > - "%s=%#x", term->config, term->val.num);
> > + "%s=%#x", config, term->val.num);
> > else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
> > ret += scnprintf(newval + ret, sizeof(newval) - ret,
> > - "%s=%s", term->config, term->val.str);
> > + "%s=%s", config, term->val.str);
> > }
> >
> > alias->name = strdup(name);
>
> But how about this alternative simple one:
>
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index e5eae23cfceb..9e5df934d22d 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -3084,7 +3084,7 @@ int parse_events_term__num(struct
> parse_events_term **term,
> struct parse_events_term temp = {
> .type_val = PARSE_EVENTS__TERM_TYPE_NUM,
> .type_term = type_term,
> - .config = config,
> + .config = config ? : strdup(config_term_names[type_term]),
> .no_value = no_value,
> .err_term = loc_term ? loc_term->first_column : 0,
> .err_val = loc_val ? loc_val->first_column : 0,
> --
If you have this change isn't the change to parse_events_term__num()
unnecessary? This 1 liner fix looks good to me.
Thanks,
Ian
> >
> > It looks like a similar fix is needed in format_alias.
>
> And the change in parse_events_term__num(), above, seems to resolve that.
>
> Previously we would have something like these in format_alias():
>
> buf=i915/bcs0-busy, pmu name=i915, alias->name=bcs0-busy ->str=(null)=0x1000
>
> And now:
>
> buf=i915/bcs0-busy, pmu name=i915, alias->name=bcs0-busy ->str=config=0x1000
>
>
> Thoughts?
>
> Thanks,
> John
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Question] perf tools: lex parsing issue
2021-08-25 16:47 ` Ian Rogers
@ 2021-08-25 16:58 ` John Garry
0 siblings, 0 replies; 5+ messages in thread
From: John Garry @ 2021-08-25 16:58 UTC (permalink / raw)
To: Ian Rogers
Cc: Jiri Olsa, Arnaldo Carvalho de Melo, linux-kernel,
linux-perf-users, Peter Zijlstra, Ingo Molnar, Mark Rutland,
Alexander Shishkin, Namhyung Kim
On 25/08/2021 17:47, Ian Rogers wrote:
> On Wed, Aug 25, 2021 at 7:32 AM John Garry<john.garry@huawei.com> wrote:
>> On 25/08/2021 01:13, Ian Rogers wrote:
>>
>> Thanks for getting back to me
>>
>>
>>>> + if (term->type_term == PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD) {
>>>> + term->config = strdup("period");
>>>> + }
>>>> +
>>>> if (!head) {
>>>> parse_events_term__delete(term);
>>>> YYABORT;
>>>> --
>>>>
>>>> ----8-----
>>> Agreed this is hacky,
>> This might be a*bit* better:
>>
>> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
>> index e5eae23cfceb..e597beaaa179 100644
>> --- a/tools/perf/util/parse-events.c
>> +++ b/tools/perf/util/parse-events.c
>> @@ -1058,6 +1058,13 @@ static const char
>> *config_term_names[__PARSE_EVENTS__TERM_TYPE_NR] = {
>> [PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE] = "aux-sample-size",
>> };
>>
>> +const char * get_config_term(int term_type)
>> +{
>> + if (term_type >= __PARSE_EVENTS__TERM_TYPE_NR)
>> + return "";
>> + return config_term_names[term_type];
>> +}
>> +
>> static bool config_term_shrinked;
>>
>> static bool
>> diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
>> index bf6e41aa9b6a..0f658732535f 100644
>> --- a/tools/perf/util/parse-events.h
>> +++ b/tools/perf/util/parse-events.h
>> @@ -90,6 +90,8 @@ enum {
>> __PARSE_EVENTS__TERM_TYPE_NR,
>> };
>>
>> +const char *get_config_term(int term_type);
>> +
>> struct parse_events_array {
>> size_t nr_ranges;
>> struct {
>> diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
>> index 9321bd0e2f76..8d6d3fae226d 100644
>> --- a/tools/perf/util/parse-events.y
>> +++ b/tools/perf/util/parse-events.y
>> @@ -832,8 +832,9 @@ PE_TERM '=' PE_NAME
>> PE_TERM '=' PE_VALUE
>> {
>> struct parse_events_term *term;
>> + char *config = strdup(get_config_term($1));
>>
>> - ABORT_ON(parse_events_term__num(&term, (int)$1, NULL, $3, false, &@1,
>> &@3));
>> + ABORT_ON(parse_events_term__num(&term, (int)$1, config, $3, false,
>> &@1, &@3));
>> $$ = term;
>> }
>>
>>
>>> I think it'd be better to fix this up in the
>>> output. For example:
>>>
>>> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
>>> index 6cdbee8a12e7..c77c42275efa 100644
>>> --- a/tools/perf/util/pmu.c
>>> +++ b/tools/perf/util/pmu.c
>>> @@ -365,15 +365,21 @@ static int __perf_pmu__new_alias(struct
>>> list_head *list, char *dir, char *name,
>>> memset(newval, 0, sizeof(newval));
>>> ret = 0;
>>> list_for_each_entry(term, &alias->terms, list) {
>>> + const char * config = term->config;
>>> +
>>> if (ret)
>>> ret += scnprintf(newval + ret, sizeof(newval) - ret,
>>> ",");
>>> + if (!config) {
>>> + /* Note: config_term_names in parse_events.c
>>> isn't accessible */
>>> + config = config_term_names[term->type_term];
>> We could just expose some parse-events.c API, like above.
>>
>>> + }
>>> if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
>>> ret += scnprintf(newval + ret, sizeof(newval) - ret,
>>> - "%s=%#x", term->config, term->val.num);
>>> + "%s=%#x", config, term->val.num);
>>> else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
>>> ret += scnprintf(newval + ret, sizeof(newval) - ret,
>>> - "%s=%s", term->config, term->val.str);
>>> + "%s=%s", config, term->val.str);
>>> }
>>>
>>> alias->name = strdup(name);
>> But how about this alternative simple one:
>>
>> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
>> index e5eae23cfceb..9e5df934d22d 100644
>> --- a/tools/perf/util/parse-events.c
>> +++ b/tools/perf/util/parse-events.c
>> @@ -3084,7 +3084,7 @@ int parse_events_term__num(struct
>> parse_events_term **term,
>> struct parse_events_term temp = {
>> .type_val = PARSE_EVENTS__TERM_TYPE_NUM,
>> .type_term = type_term,
>> - .config = config,
>> + .config = config ? : strdup(config_term_names[type_term]),
>> .no_value = no_value,
>> .err_term = loc_term ? loc_term->first_column : 0,
>> .err_val = loc_val ? loc_val->first_column : 0,
>> --
> If you have this change isn't the change to parse_events_term__num()
> unnecessary?
eh, this is parse_events_term__num().
Anyway, yes, this 1-line change in parse_events_term__num() only does
look to fix it. More testing required, though.
This 1 liner fix looks good to me.
Cheers,
John
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2021-08-23 11:27 [Question] perf tools: lex parsing issue John Garry
2021-08-25 0:13 ` Ian Rogers
2021-08-25 14:36 ` John Garry
2021-08-25 16:47 ` Ian Rogers
2021-08-25 16:58 ` John Garry
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