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Subject: Re: [PATCH v2 3/4] perf tools: Add printing perf_event_attr type
 symbol in perf_event_attr__fprintf()
To:     Adrian Hunter <adrian.hunter@intel.com>, <peterz@infradead.org>,
        <mingo@redhat.com>, <acme@kernel.org>, <mark.rutland@arm.com>,
        <alexander.shishkin@linux.intel.com>, <jolsa@kernel.org>,
        <namhyung@kernel.org>, <irogers@google.com>,
        <anshuman.khandual@arm.com>, <jesussanp@google.com>,
        <linux-perf-users@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20230511075154.240163-1-yangjihong1@huawei.com>
 <20230511075154.240163-4-yangjihong1@huawei.com>
 <0be18c9a-ab56-021f-5c51-8b066ead2e1c@intel.com>
From:   Yang Jihong <yangjihong1@huawei.com>
Message-ID: <ca0f27b5-bf0a-6ae3-a05c-84a456b02fcf@huawei.com>
Date:   Mon, 15 May 2023 16:48:54 +0800
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Hello,

On 2023/5/12 18:34, Adrian Hunter wrote:
> On 11/05/23 10:51, Yang Jihong wrote:
>> When printing perf_event_attr, always display perf_event_attr type and its symbol
>> to improve the readability of debugging information.
>>
>> Before:
>>
>>    # perf --debug verbose=2 record -e cycles,cpu-clock,sched:sched_switch,branch-load-misses,r101,mem:0x0 -C 0 true
>>    <SNIP>
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      size                             136
>>      { sample_period, sample_freq }   4000
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      freq                             1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             1
>>      size                             136
>>      { sample_period, sample_freq }   4000
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      freq                             1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 6
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             2
>>      size                             136
>>      config                           0x143
>>      { sample_period, sample_freq }   1
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 7
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             3
>>      size                             136
>>      config                           0x10005
>>      { sample_period, sample_freq }   4000
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      freq                             1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 9
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             4
>>      size                             136
>>      config                           0x101
>>      { sample_period, sample_freq }   4000
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      freq                             1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 10
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             5
>>      size                             136
>>      { sample_period, sample_freq }   1
>>      sample_type                      IP|TID|TIME|CPU|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>      bp_type                          3
>>      { bp_len, config2 }              0x4
>>    ------------------------------------------------------------
>>    <SNIP>
>>
>> After:
>>
>>    # perf --debug verbose=2 record -e cycles,cpu-clock,sched:sched_switch,branch-load-misses,r101,mem:0x0 -C 0 true
>>    <SNIP>
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             0 (PERF_TYPE_HARDWARE)
>>      size                             136
>>      { sample_period, sample_freq }   4000
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      freq                             1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             1 (PERF_TYPE_SOFTWARE)
>>      size                             136
>>      { sample_period, sample_freq }   4000
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      freq                             1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 6
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             2 (PERF_TYPE_TRACEPOINT)
>>      size                             136
>>      config                           0x143
>>      { sample_period, sample_freq }   1
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 7
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             3 (PERF_TYPE_HW_CACHE)
>>      size                             136
>>      config                           0x10005
>>      { sample_period, sample_freq }   4000
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      freq                             1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 9
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             4 (PERF_TYPE_RAW)
>>      size                             136
>>      config                           0x101
>>      { sample_period, sample_freq }   4000
>>      sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      freq                             1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>    ------------------------------------------------------------
>>    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 10
>>    ------------------------------------------------------------
>>    perf_event_attr:
>>      type                             5 (PERF_TYPE_BREAKPOINT)
>>      size                             136
>>      { sample_period, sample_freq }   1
>>      sample_type                      IP|TID|TIME|CPU|IDENTIFIER
>>      read_format                      ID
>>      disabled                         1
>>      inherit                          1
>>      sample_id_all                    1
>>      exclude_guest                    1
>>      bp_type                          3
>>      { bp_len, config2 }              0x4
>>    ------------------------------------------------------------
>>    <SNIP>
>>
>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
>> ---
>>   tools/perf/util/perf_event_attr_fprintf.c | 30 ++++++++++++++++++++++-
>>   1 file changed, 29 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/perf_event_attr_fprintf.c b/tools/perf/util/perf_event_attr_fprintf.c
>> index 433029c6afc5..cd0905d8cb7a 100644
>> --- a/tools/perf/util/perf_event_attr_fprintf.c
>> +++ b/tools/perf/util/perf_event_attr_fprintf.c
>> @@ -71,6 +71,33 @@ static void __p_read_format(char *buf, size_t size, u64 value)
>>   	__p_bits(buf, size, value, bits);
>>   }
>>   
>> +#define ENUM_ID_TO_STR_CASE(x) case x: return (#x);
>> +static const char *stringify_perf_type_id(u64 value)
>> +{
>> +	/* sync with enum perf_type_id in perf_event.h */
> 
> Everything in this file syncs with perf_event.h, so the comment
> does not seem very useful.
OK, will fix in v3.
> 
>> +	switch (value) {
>> +	ENUM_ID_TO_STR_CASE(PERF_TYPE_HARDWARE)
>> +	ENUM_ID_TO_STR_CASE(PERF_TYPE_SOFTWARE)
>> +	ENUM_ID_TO_STR_CASE(PERF_TYPE_TRACEPOINT)
>> +	ENUM_ID_TO_STR_CASE(PERF_TYPE_HW_CACHE)
>> +	ENUM_ID_TO_STR_CASE(PERF_TYPE_RAW)
>> +	ENUM_ID_TO_STR_CASE(PERF_TYPE_BREAKPOINT)
>> +	default:
>> +		return NULL;
>> +	}
>> +}
>> +#undef ENUM_ID_TO_STR_CASE
>> +
>> +static void __p_type_id(char *buf, size_t size, u64 value)
>> +{
>> +	const char *str = stringify_perf_type_id(value);
>> +
>> +	if (str == NULL)
>> +		snprintf(buf, size, "%"PRIu64, value);
>> +	else
>> +		snprintf(buf, size, "%"PRIu64" (%s)", value, str);
> 
> These 4 lines end up getting used again about 3 times in the next
> patch, so might as well be a separate function e.g.
> 
> 	print_id(buf, size, value, stringify_perf_type_id(value));
> 
> where:
> 
> static void print_id(char *buf, size_t size, u64 value, const char *str)
> {
> 	if (str == NULL)
> 		snprintf(buf, size, "%"PRIu64, value);
> 	else
> 		snprintf(buf, size, "%"PRIu64" (%s)", value, str);
> }
> 
OK, will add print_id() helper in v3.
If print_id() helper is also used to print config id, is printed in the 
decimal format. In the past, it is printed in the hexadecimal format，
there may be some changes here.

Before:
   config                           0x143

After:
   config                           323 (sched:sched_switch)

>> +}
>> +
>>   #define BUF_SIZE		1024
>>   
>>   #define p_hex(val)		snprintf(buf, BUF_SIZE, "%#"PRIx64, (uint64_t)(val))
>> @@ -79,6 +106,7 @@ static void __p_read_format(char *buf, size_t size, u64 value)
>>   #define p_sample_type(val)	__p_sample_type(buf, BUF_SIZE, val)
>>   #define p_branch_sample_type(val) __p_branch_sample_type(buf, BUF_SIZE, val)
>>   #define p_read_format(val)	__p_read_format(buf, BUF_SIZE, val)
>> +#define p_type_id(val)		__p_type_id(buf, BUF_SIZE, val)
>>   
>>   #define PRINT_ATTRn(_n, _f, _p, _a)			\
>>   do {							\
>> @@ -96,7 +124,7 @@ int perf_event_attr__fprintf(FILE *fp, struct perf_event_attr *attr,
>>   	char buf[BUF_SIZE];
>>   	int ret = 0;
>>   
>> -	PRINT_ATTRf(type, p_unsigned);
>> +	PRINT_ATTRn("type", type, p_type_id, true);
>>   	PRINT_ATTRf(size, p_unsigned);
>>   	PRINT_ATTRf(config, p_hex);
>>   	PRINT_ATTRn("{ sample_period, sample_freq }", sample_period, p_unsigned, false);
> 
> .
>