linux-kernel - Re: [PATCH 2/2 v4] sched: Rewrite per entity runnable load average tracking

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:	Tue, 29 Jul 2014 08:56:41 +0800
From:	Yuyang Du <yuyang.du@...el.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	mingo@...hat.com, linux-kernel@...r.kernel.org, pjt@...gle.com,
	bsegall@...gle.com, arjan.van.de.ven@...el.com,
	len.brown@...el.com, rafael.j.wysocki@...el.com,
	alan.cox@...el.com, mark.gross@...el.com, fengguang.wu@...el.com
Subject: Re: [PATCH 2/2 v4] sched: Rewrite per entity runnable load average
 tracking

On Mon, Jul 28, 2014 at 12:48:37PM +0200, Peter Zijlstra wrote:
> > +static __always_inline u64 decay_load(u64 val, u64 n)
> > +{
> > +	if (likely(val <= UINT_MAX))
> > +		val = decay_load32(val, n);
> > +	else {
> > +		val *= (u32)decay_load32(1 << 15, n);
> > +		val >>= 15;
> > +	}
> > +
> > +	return val;
> > +}
> 
> Please just use mul_u64_u32_shr().
> 
> /me continues reading the rest of it..

Good. Since 128bit is considered in mul_u64_u32_shr, load_sum can
afford more tasks :)
--
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/