linux-kernel - Re: Stolen and degraded time and schedulers

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: <45F85A62.8050001@vmware.com>
Date:	Wed, 14 Mar 2007 13:26:10 -0700
From:	Dan Hecht <dhecht@...are.com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
CC:	dwalker@...sta.com, cpufreq@...ts.linux.org.uk,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Con Kolivas <kernel@...ivas.org>,
	Chris Wright <chrisw@...s-sol.org>,
	Virtualization Mailing List <virtualization@...ts.osdl.org>,
	john stultz <johnstul@...ibm.com>, Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>, paulus@...ibm.com,
	schwidefsky@...ibm.com, Rik van Riel <riel@...hat.com>
Subject: Re: Stolen and degraded time and schedulers


>>> How is cpustat->steal used?  How does it get out to usermode?
>>>
>> Via /proc/stat, used by modern 'top', maybe other utilities.  It is
>> useful to users who want to see where the time is really going from
>> inside a guest when running on a (para)virtual machine.
>>
>> I believe previous set of xen paravirt-ops patches already handled
>> cases #2 and #3 (but no longer do since switching to clockevents), and
>> the old vmitime code did also.  Obviously, we need revamp this stuff
>> to make it fit in with the new clockevents/hrtimer way of doing things.
> 
> I added stolen time accounting to xen-pv_ops last night.  For Xen, at
> least, it wasn't hard to fit into the clockevent infrastructure.  I just
> update the stolen time accounting for each cpu when it gets a timer
> tick; they seem to get a tick every couple of seconds even when idle.
> 

Sounds good.  I don't see this in your patchset you sent yesterday 
though; did you add it after sending out those patches?  if so, could 
you forward the new patch?  does it explicitly prevent stolen time from 
getting accounted as  user/system time or does it just rely on NO_HZ 
mode sort of happening to work that way (since the one shot timer is 
skipped ahead for missed ticks)?

thanks,
Dan
-
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/