linux-kernel - Re: [RFC PATCH 01/14] sched: track the runnable average on a per-task entitiy basis

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 for Android: free password hash cracker in your pocket

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

Message-ID: <CAPM31RKkh73tKfDyT25ayS3qN1pv3jcNVfNoso2qRAwS2X3Y=g@mail.gmail.com>
Date:	Fri, 17 Feb 2012 03:44:05 -0800
From:	Paul Turner <pjt@...gle.com>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	linux-kernel@...r.kernel.org, Venki Pallipadi <venki@...gle.com>,
	Srivatsa Vaddagiri <vatsa@...ibm.com>,
	Mike Galbraith <efault@....de>,
	Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>,
	Ben Segall <bsegall@...gle.com>, Ingo Molnar <mingo@...e.hu>,
	Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>
Subject: Re: [RFC PATCH 01/14] sched: track the runnable average on a per-task
 entitiy basis

On Thu, Feb 16, 2012 at 5:27 AM, Peter Zijlstra <a.p.zijlstra@...llo.nl> wrote:
> On Wed, 2012-02-01 at 17:38 -0800, Paul Turner wrote:
>> +static __always_inline u64 decay_load(u64 val, int n)
>> +{
>> +       for (;n && val;n--) {
>> +               val *= 4008;
>> +               val >>= 12;
>> +       }
>> +
>> +       return val;
>> +}
>
>> +                       sa->runnable_avg_sum =
>> +                               decay_load(sa->runnable_avg_sum, 1);
>> +                       sa->runnable_avg_period =
>> +                               decay_load(sa->runnable_avg_period, 1);
>
> Since all you ever seem to do is:
>
>  x = decay(x, n);
>
> and frequently run over the line limits it might make sense to either
> introduce a CPP helper or make the first argument a pointer and ditch
> the return value so we end up with something like:
>
>  decay(&x, n);

Ah-ha, good idea.  I had done some other fiddles to try and make
things fit better, but this will work.

Thanks!
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/