linux-kernel - Re: nohz and strange sleep latencies

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: <alpine.LFD.0.9999.0711202345520.25057@localhost.localdomain>
Date:	Tue, 20 Nov 2007 23:48:02 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Ingo Molnar <mingo@...e.hu>
cc:	Pavel Machek <pavel@....cz>,
	kernel list <linux-kernel@...r.kernel.org>
Subject: Re: nohz and strange sleep latencies

On Tue, 20 Nov 2007, Ingo Molnar wrote:
> 
> * Pavel Machek <pavel@....cz> wrote:
> 
> > > and send us the output? (Enabling CONFIG_TIMER_STATS, 
> > > CONFIG_SCHED_DEBUG and CONFIG_SCHEDSTATS would maximize the amount 
> > > of information.)
> > 
> > This was w/o hpet=disable . Do you want me to test with hpet=disable?
> 
> no, this is fine. You've got a hpet clockevents driver and two lapic 
> drivers:
> 
> Clock Event Device: hpet
>  set_next_event: hpet_legacy_next_event
>  set_mode:       hpet_legacy_set_mode
>  event_handler:  tick_handle_oneshot_broadcast
> 
> Clock Event Device: lapic
>  set_next_event: lapic_next_event
>  set_mode:       lapic_timer_setup
>  event_handler:  hrtimer_interrupt
> 
> Clock Event Device: lapic
>  set_next_event: lapic_next_event
>  set_mode:       lapic_timer_setup
>  event_handler:  hrtimer_interrupt
> 
> to me this has the feeling of lapic breakage in C2 mode. Does it get any 
> better if you boot with 'nolapic'? (but that might in turn turn off 
> high-res timers and nohz in essence) Thomas, any ideas?

Hmm, lapic is considered unstable in c2 by default. You have to tell
the kernel that you trust it in C2 on the command line.

/me goes back to read the logs

    tglx
-
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/