linux-kernel - Re: [PATCH] tracing, perf: add more power related events

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: <201009282322.16291.rjw@sisk.pl>
Date:	Tue, 28 Sep 2010 23:22:15 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Jean Pihet <jean.pihet@...oldbits.com>
Cc:	Thomas Renninger <trenn@...e.de>, Ingo Molnar <mingo@...e.hu>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Len Brown <len.brown@...el.com>, arjan@...radead.org,
	Kevin Hilman <khilman@...prootsystems.com>,
	linux-kernel@...r.kernel.org, linux-pm@...ts.linux-foundation.org,
	linux-omap@...r.kernel.org, linux-perf-users@...r.kernel.org,
	linux-trace-users@...r.kernel.org
Subject: Re: [PATCH] tracing, perf: add more power related events

On Tuesday, September 28, 2010, Jean Pihet wrote:
> Hi,

Hi,

> Here is what I am proposing, in reply to all your comments:
> 
> 1) rename the events to match Thomas's proposal:
>    power:power_cpu_cstate
>    power:power_cpu_pstate
>    power:power_cpu_sstate

If that sstate thing is going to mean "suspend", then please drop it.
"Suspend" is not a state, let alone a CPU state.  It is a procedure by which
the (entire) system is put into a sleep state (that is not confined to CPUs).

>    ...
> 
> 2) introduce a new Kconfig option CONFIG_DEPRECATED_POWER_EVENTS and
> conditionally map a subset of the new events to the old ones for
> backward compatibility with the existing user apps. The apps should be
> converted to the new API asap,
> 
> 3) update documentation

Sounds reasonable.

> Other remarks here below:
> 
> On Wed, Sep 22, 2010 at 8:49 PM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> ...
> > This POWER_SSTATE thing seems to be totally artificial and omap-specific.
> >
> > Why do you want it to be done this way?
> >
> > Or is the ACPI handling added in the ACPI patch?  In which case, why don't you
> > put that power_switch_state(POWER_SSTATE, 1, 0, cpu) into
> > kernel/power/suspend.c:suspend_enter() (and analogously for
> > power_switch_state(POWER_SSTATE, 0, 0, cpu)).
> The ACPI code is not using the SSTATE event.
> Indeed inserting a tracepoint at
> kernel/power/suspend.c:suspend_enter() is more generic. I will correct
> this.

OK

> > Moreover, why is the cpu argument necessary for POWER_SSTATE at all?
> The cpu_id parameter is present in all events prototypes. This is not
> needed. I will correct this.

OK

Thanks,
Rafael
--
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/