linux-kernel - Re: [PATCH v2 3/3] sched: increase SCHED_LOAD

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]

Message-ID: <20110518182519.GB25881@elte.hu>
Date:	Wed, 18 May 2011 20:25:19 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Nikhil Rao <ncrao@...gle.com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Mike Galbraith <efault@....de>, linux-kernel@...r.kernel.org,
	"Nikunj A. Dadhania" <nikunj@...ux.vnet.ibm.com>,
	Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
	Stephan Barwolf <stephan.baerwolf@...ilmenau.de>
Subject: Re: [PATCH v2 3/3] sched: increase SCHED_LOAD_SCALE resolution


* Nikhil Rao <ncrao@...gle.com> wrote:

> -#define SCHED_LOAD_SHIFT	10
> +#if BITS_PER_LONG > 32
> +#define SCHED_LOAD_RESOLUTION	10
> +#define scale_load(w)		(w << SCHED_LOAD_RESOLUTION)
> +#define scale_load_down(w)	(w >> SCHED_LOAD_RESOLUTION)
> +#else
> +#define SCHED_LOAD_RESOLUTION	0
> +#define scale_load(w)		w
> +#define scale_load_down(w)	w
> +#endif

Please use the:

#if X
# define Y A
#else
# define Y B
#endif

type of nested CPP branching style.

Also, the 'w' probably wants to be '(w)', just in case.

>  	if (!lw->inv_weight) {
> -		if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
> +		unsigned long w = scale_load_down(lw->weight);
> +		if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
>  			lw->inv_weight = 1;

Please separate local variable declarations and the first statement following 
it by an extra empty line.

Could you also put all the performance measurement description into the 
changelog of this third commit - so that people can see (and enjoy) the 
extensive testing you have done on this topic?

Thanks,

	Ingo
--
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/