Re: [PATCH 3/4] perf tools: Add printing perf_event_attr->type symbol in perf_event_attr__fprintf()
From: Adrian Hunter
Date: Wed May 10 2023 - 11:52:18 EST
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@xxxxxxxxxx>
>> ---
>> 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);
>