From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Luming Yu <luming.yu@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Len Brown <lenb@kernel.org>,
"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
"Siddha, Suresh B" <suresh.b.siddha@intel.com>,
Arjan van de Ven <arjan@linux.intel.com>
Subject: Re: [RFC PATCH] use acpi_idle_enter_simple if bm_check && !.bm_control
Date: Mon, 19 Apr 2010 18:47:37 +0100 [thread overview]
Message-ID: <20100419174737.GA13331@srcf.ucam.org> (raw)
In-Reply-To: <3877989d0911092212i367b9156n78d57aeee6742147@mail.gmail.com>
On Tue, Nov 10, 2009 at 02:12:41PM +0800, Luming Yu wrote:
> I came across acpi processor idle driver, noticed that we can cut a
> bit overhead at C3 entry that can improve C3 residency a bit,
> especially when it has similar kernel config as old RHEL 5 kernel
> (2.6.18) on systems with as many as 64 logical CPUs. The point of this
> patch is bm_sts is an optional bit. It never returns 1 on systems with
> bm_check && !bm_control I tested. Instead, I have observed lower C3
> residency due to accessing bm_sts and relevant code on a system with
> 64 logical CPUs with HZ=1000. Please review. If make sense, please
> apply.
Saves 40W or so on a dual-socket Nehalem system here. Is there a reason
it wasn't picked up?
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2010-04-19 17:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-10 6:12 [RFC PATCH] use acpi_idle_enter_simple if bm_check && !.bm_control Luming Yu
2010-04-19 17:47 ` Matthew Garrett [this message]
2010-07-21 21:29 ` Len Brown
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