linux-kernel - Re: Patch for tracing c states (power

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:	Wed, 24 Feb 2010 16:36:42 +0800
From:	Li Zefan <lizf@...fujitsu.com>
To:	Robert Schöne <robert.schoene@...dresden.de>
CC:	Arjan van de Ven <arjan@...ux.intel.com>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	kernel list <linux-kernel@...r.kernel.org>
Subject: Re: Patch for tracing c states (power_end) on x86

Robert Schöne wrote:
> Hello,
> 
> Since noone replied to my last mail (Febr. 15th, 11:42), describing the
> way to fix the missing c-state tracing, here's a patch.
> Maybe its easier that way.
> 
> (I used the perf-fixes-for-linus git tree to obtain a
> more-then-up-to-date version)
> 
> Bye Robert
> 
> 
> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> index 02d6780..b1cfb88 100644
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -384,6 +384,7 @@ void default_idle(void)
>                 else
>                         local_irq_enable();
>                 current_thread_info()->status |= TS_POLLING;
> +               trace_power_end(1);
>         } else {
>                 local_irq_enable();
>                 /* loop is done by the caller */
> @@ -451,6 +452,7 @@ void mwait_idle_with_hints(unsigned long ax,
> unsigned long cx)
>                 if (!need_resched())
>                         __mwait(ax, cx);
>         }
> +       trace_power_end((ax>>4)+1);

The only argument of trace_power_end() is a dummy, so you can just
pass 0 or 1 to the trace hook, actually better pass 0 to be
consistent with other parts.

The dummy argument can't be eliminated, because the macros that
automatically generates racing code have some limitations, and
seems it's not so easy to get over.

>  }
>  
>  /* Default MONITOR/MWAIT with no hints, used for default C1 state */
> @@ -467,6 +469,7 @@ static void mwait_idle(void)
>                         __sti_mwait(0, 0);
>                 else
>                         local_irq_enable();
> +               trace_power_end(1);
>         } else
>                 local_irq_enable();
>  }
> 
> 
--
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/