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, 11 Oct 2011 10:18:19 +0800
From:	Ming Lei <tom.leiming@...il.com>
To:	Shaohua Li <shli@...nel.org>
Cc:	Alan Cox <alan@...rguk.ukuu.org.uk>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	mark gross <mgross@...ux.intel.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux PM List <linux-pm@...r.kernel.org>
Subject: Re: [Question] PM-QoS: PM_QOS_CPU_DMA_LATENCY == interrupt latency?

Hi,

On Tue, Oct 11, 2011 at 9:49 AM, Shaohua Li <shli@...nel.org> wrote:

> As Alan explained, PM_QOS_CPU_DMA_LATENCY is for dma snooping. For example,
> in x86, cpu snoop dma. when cpu is in idle state, cpu need snoop
> device dma activity, there
> is latency involved for idle state.
>

I see, thanks for your clarification.

I also have two further questions about it:

- Except for dma snooping purpose, are there any other cases in which
PM_QOS_CPU_DMA_LATENCY is required?

- Are all CPUs required to be involved to dma snoop? Or only one CPU
is enough? If one is enough, maybe we can allow other CPUs to reach
deeper idle state.


thanks,
-- 
Ming Lei
--
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/

Powered by blists - more mailing lists