Re: [RFC PATCH 1/6] sched/fair: Add util_guest for tasks

[David Dai]

On Wed, Apr 5, 2023 at 1:14 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>

Hi Peter,

Appreciate your time,

> On Thu, Mar 30, 2023 at 03:43:36PM -0700, David Dai wrote:
> > @@ -499,6 +509,7 @@ struct sched_avg {
> >       unsigned long                   load_avg;
> >       unsigned long                   runnable_avg;
> >       unsigned long                   util_avg;
> > +     unsigned long                   util_guest;
> >       struct util_est                 util_est;
> >  } ____cacheline_aligned;
> >
>
> Yeah, no... you'll have to make room first.
>

I’m not sure what you mean. Do you mean making room by reducing
another member in the same struct? If so, which member would be a good
fit to shorten? Or do you mean something else entirely?

Thanks,
David

> struct sched_avg {
>         /* typedef u64 -> __u64 */ long long unsigned int     last_update_time;          /*     0     8 */
>         /* typedef u64 -> __u64 */ long long unsigned int     load_sum;                  /*     8     8 */
>         /* typedef u64 -> __u64 */ long long unsigned int     runnable_sum;              /*    16     8 */
>         /* typedef u32 -> __u32 */ unsigned int               util_sum;                  /*    24     4 */
>         /* typedef u32 -> __u32 */ unsigned int               period_contrib;            /*    28     4 */
>         long unsigned int          load_avg;                                             /*    32     8 */
>         long unsigned int          runnable_avg;                                         /*    40     8 */
>         long unsigned int          util_avg;                                             /*    48     8 */
>         struct util_est {
>                 unsigned int       enqueued;                                             /*    56     4 */
>                 unsigned int       ewma;                                                 /*    60     4 */
>         } __attribute__((__aligned__(8)))util_est __attribute__((__aligned__(8))); /*    56     8 */
>
>         /* size: 64, cachelines: 1, members: 9 */
>         /* forced alignments: 1 */
> } __attribute__((__aligned__(64)));
>
>