linux-kernel - Re: [PATCH v3 0/6] cpufreq: schedutil: fixes for flags updates

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 21 Dec 2017 14:45:02 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Patrick Bellasi <patrick.bellasi@....com>,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Ingo Molnar <mingo@...hat.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Todd Kjos <tkjos@...roid.com>,
        Joel Fernandes <joelaf@...gle.com>
Subject: Re: [PATCH v3 0/6] cpufreq: schedutil: fixes for flags updates

On 20-12-17, 16:43, Peter Zijlstra wrote:
> The below makes more sense to me too; hmm?
> 
> @@ -335,12 +335,11 @@ static unsigned int sugov_next_freq_shar
>  
>  		j_max = j_sg_cpu->max;
>  		j_util = sugov_aggregate_util(j_sg_cpu);
> +		sugov_iowait_boost(j_sg_cpu, &util, &max);
>  		if (j_util * max > j_max * util) {
>  			util = j_util;
>  			max = j_max;
>  		}
> -
> -		sugov_iowait_boost(j_sg_cpu, &util, &max);

Sorry if I am being a fool here, I had 3 different interpretations of
the results after this change in the last 15 minutes. It was confusing
for somehow..

Why do you think above change matters ? I think nothing changed after
this diff at all.

We have three different values here:

util/max, j_util/j_max, and j_boost_util/j_boost_max.

And we are trying to find the max among them and changing the order of
comparisons doesn't change anything.

Am I reading the code correctly ?

-- 
viresh