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Message-ID: <5267232a-05a4-393b-b68e-da6a4f46d5e8@intel.com>
Date:   Wed, 10 May 2023 18:51:55 +0300
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Subject: Re: [PATCH 3/4] perf tools: Add printing perf_event_attr->type symbol
 in perf_event_attr__fprintf()
Content-Language: en-US
From:   Adrian Hunter <adrian.hunter@intel.com>
To:     Yang Jihong <yangjihong1@huawei.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: <20230419122912.73746-1-yangjihong1@huawei.com>
 <20230419122912.73746-4-yangjihong1@huawei.com>
 <09511964-dea6-f078-b24c-fef6b05f5b79@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
 Business Identity Code: 0357606 - 4, Domiciled in Helsinki
In-Reply-To: <09511964-dea6-f078-b24c-fef6b05f5b79@intel.com>
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On 10/05/23 11:32, Adrian Hunter wrote:
> On 19/04/23 15:29, Yang Jihong wrote:
>> When printing perf_event_attr, always display 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 -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 = 6
>>   ------------------------------------------------------------
>>   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 = 7
>>   ------------------------------------------------------------
>>   perf_event_attr:
>>     type                             2
>>     size                             136
>>     config                           0x131
>>     { 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 = 8
>>   ------------------------------------------------------------
>>   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 = 10
>>   ------------------------------------------------------------
>>   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 = 11
>>   <SNIP>
>>
>> After:
>>
>>   # perf --debug verbose=2 record -e cycles,cpu-clock,sched:sched_switch,branch-load-misses,r101 -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 = 6
>>   ------------------------------------------------------------
>>   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 = 7
>>   ------------------------------------------------------------
>>   perf_event_attr:
>>     type                             2 (PERF_TYPE_TRACEPOINT)
>>     size                             136
>>     config                           0x131
>>     { 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 = 8
>>   ------------------------------------------------------------
>>   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 = 10
>>   ------------------------------------------------------------
>>   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 = 11
>>   <SNIP>
>>
>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
>> ---
>>  tools/perf/util/perf_event_attr_fprintf.c | 24 ++++++++++++++++++++++-
>>  1 file changed, 23 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..d9d70126d505 100644
>> --- a/tools/perf/util/perf_event_attr_fprintf.c
>> +++ b/tools/perf/util/perf_event_attr_fprintf.c
>> @@ -71,6 +71,27 @@ static void __p_read_format(char *buf, size_t size, u64 value)
>>  	__p_bits(buf, size, value, bits);
>>  }
>>  
>> +static void __p_type_id(char *buf, size_t size, u64 value)
>> +{
>> +	/* sync with enum perf_type_id in perf_event.h */
>> +	switch (value) {
>> +#define PRINT_ENUM_PERF_TYPE_ID_CASE(x)					\
>> +	case x:								\
>> +		snprintf(buf, size, "%"PRIu64" (%s)", value, #x);	\
>> +		return;
>> +	PRINT_ENUM_PERF_TYPE_ID_CASE(PERF_TYPE_HARDWARE)
>> +	PRINT_ENUM_PERF_TYPE_ID_CASE(PERF_TYPE_SOFTWARE)
>> +	PRINT_ENUM_PERF_TYPE_ID_CASE(PERF_TYPE_TRACEPOINT)
>> +	PRINT_ENUM_PERF_TYPE_ID_CASE(PERF_TYPE_HW_CACHE)
>> +	PRINT_ENUM_PERF_TYPE_ID_CASE(PERF_TYPE_RAW)
>> +	PRINT_ENUM_PERF_TYPE_ID_CASE(PERF_TYPE_BREAKPOINT)
>> +#undef PRINT_ENUM_PERF_TYPE_ID_CASE
> 
> These are ABI constants so maybe simpler:
> 
> 	const char *fixed_types[] = {"HARDWARE", "SOFTWARE", "TRACEPOINT",
> 				     "HW_CACHE", "RAW", "BREAKPOINT"};
> 
> 	if (value < ARRAY_SIZE(fixed_types)) {
> 		snprintf(buf, size, "%"PRIu64" (PERF_TYPE_%s)",
> 			 value, fixed_types[value]);
> 	} else {
> 		snprintf(buf, size, "%"PRIu64, value);
> 	}

Although it is really the repeated snprintf that seems unnecessary
so maybe use a switch but just to get the stringified name.

> 
>> +	default:
>> +		snprintf(buf, size, "%"PRIu64, value);
>> +		return;
>> +	}
>> +}
>> +
>>  #define BUF_SIZE		1024
>>  
>>  #define p_hex(val)		snprintf(buf, BUF_SIZE, "%#"PRIx64, (uint64_t)(val))
>> @@ -79,6 +100,7 @@ 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 +118,7 @@ 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);
>