Re: [RFC 10/10] trace: platform/x86/intel/ifs: Add trace point to track Intel IFS operations

Joseph, Jithu
2022-03-02T01:02:43Z

On 3/1/2022 12:17 PM, Steven Rostedt wrote:
> On Tue, 1 Mar 2022 11:54:57 -0800
> Jithu Joseph <jithu.joseph@intel.com> wrote:
>
>> + TP_STRUCT__entry(
>> + __field( u8, start )
>> + __field( u8, stop )
>> + __field( u64, status )
>> + ),
>
> I'd suggest swapping this to:
>
> __field( u64, status )
> __field( u8, start )
> __field( u8, stop )
>
> As trace events are usually aligned by 4 bytes (sometimes 8 for archs that
> require 8byte alignment for 8 byte words), but any event, putting the
> padding at the end of the event is better than in the middle of the event.
>
> Having the u64 come after two u8 (two byes) will pretty much guarantee a 6
> bytes hole in the middle of the event.

Will reorder the fields as you suggested. Appreciate the detailed comment.

Jithu