by Yang Jihong

[permalink] [raw]

Subject: Re: [PATCH 3/4] perf tools: Add printing perf_event_attr->type symbol in perf_event_attr__fprintf()

Hello,

On 2023/5/10 23:51, Adrian Hunter wrote:
> 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 <[email protected]>
>>> ---
>>> 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.
>
Ok, will use switch/case to get stringified name for type and id in v2.

Thanks,
Yang