linux-kernel - Re: [RFC PATCH v7 11/23] sched/fair: core wide cfs task priority comparison

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Date:   Thu, 17 Sep 2020 16:39:53 -0400
From:   Vineeth Pillai <viremana@...ux.microsoft.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Julien Desfossez <jdesfossez@...italocean.com>
Cc:     Joel Fernandes <joelaf@...gle.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Aaron Lu <aaron.lwe@...il.com>,
        Aubrey Li <aubrey.intel@...il.com>,
        Dhaval Giani <dhaval.giani@...cle.com>,
        Chris Hyser <chris.hyser@...cle.com>,
        Nishanth Aravamudan <naravamudan@...italocean.com>,
        mingo@...nel.org, tglx@...utronix.de, pjt@...gle.com,
        torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org,
        fweisbec@...il.com, keescook@...omium.org, kerrnel@...gle.com,
        Phil Auld <pauld@...hat.com>,
        Valentin Schneider <valentin.schneider@....com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>, joel@...lfernandes.org,
        vineeth@...byteword.org, Chen Yu <yu.c.chen@...el.com>,
        Christian Brauner <christian.brauner@...ntu.com>,
        Agata Gruza <agata.gruza@...el.com>,
        Antonio Gomez Iglesias <antonio.gomez.iglesias@...el.com>,
        graf@...zon.com, konrad.wilk@...cle.com, dfaggioli@...e.com,
        rostedt@...dmis.org, derkling@...gle.com, benbjiang@...cent.com,
        Aaron Lu <ziqian.lzq@...fin.com>
Subject: Re: [RFC PATCH v7 11/23] sched/fair: core wide cfs task priority
 comparison


> +
> +bool cfs_prio_less(struct task_struct *a, struct task_struct *b)
> +{
> +       struct sched_entity *se_a = &a->se, *se_b = &b->se;
> +       struct cfs_rq *cfs_rq_a, *cfs_rq_b;
> +       u64 vruntime_a, vruntime_b;
> +
> +#ifdef CONFIG_FAIR_GROUP_SCHED
> +       while (!is_same_tg(se_a, se_b)) {
> +               int se_a_depth = se_a->depth;
> +               int se_b_depth = se_b->depth;
> +
> +               if (se_a_depth <= se_b_depth)
> +                       se_b = parent_entity(se_b);
> +               if (se_a_depth >= se_b_depth)
> +                       se_a = parent_entity(se_a);
> +       }
> +#endif
> +
> +       cfs_rq_a = cfs_rq_of(se_a);
> +       cfs_rq_b = cfs_rq_of(se_b);
> +
> +       vruntime_a = se_a->vruntime - cfs_rq_a->min_vruntime;
> +       vruntime_b = se_b->vruntime - cfs_rq_b->min_vruntime;
> +
> +       trace_printk("(%s/%d;%Ld,%Lu) ?< (%s/%d;%Ld,%Lu)\n",
> +                    a->comm, a->pid, vruntime_a, cfs_rq_a->core_lag,
> +                    b->comm, b->pid, vruntime_b, cfs_rq_b->core_lag);
> +       if (cfs_rq_a != cfs_rq_b) {
> +               vruntime_a -= calc_delta_fair(cfs_rq_a->core_lag, 
> &a->se);
> +               vruntime_b -= calc_delta_fair(cfs_rq_b->core_lag, 
> &b->se);

This should be:
+               vruntime_a -= calc_delta_fair(cfs_rq_a->core_lag, se_a);
+               vruntime_b -= calc_delta_fair(cfs_rq_b->core_lag, se_b);


Thanks,
Vineeth