Re: [PATCH v2 2/6] perf record: Get the first sample time and last sample time

[Jin, Yao]

On 9/27/2017 8:16 PM, Jiri Olsa wrote:
> On Tue, Sep 26, 2017 at 06:57:58PM +0800, Jin Yao wrote:
>> In perf record, it's walked on all samples yet. So it's very easy to get
>> the first/last samples and save the time to perf file header via the
>> function write_sample_time().
>>
>> In later, perf report/script will fetch the time from perf file header.
>>
>> Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
>> ---
>>  tools/perf/builtin-record.c | 17 +++++++++++++++++
>>  1 file changed, 17 insertions(+)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index 9b379f3..3428633 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -80,6 +80,8 @@ struct record {
>>  	bool			timestamp_filename;
>>  	struct switch_output	switch_output;
>>  	unsigned long long	samples;
>> +	u64			first_sample_time;
>> +	u64			last_sample_time;
> 
> so we have those 2 u64 already in 3 structs: evlist, session and now record
> 
> can't we do that with just in one? I'd think all of them should be available
> and reachable everywhere
> 
> jirka
> 

Thanks! 

Yes, you are right. It looks we only need to define them in evlist.

If no other comments, I will prepare v3 to fix this.

Thanks
Jin Yao