From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Luck, Tony" Date: Mon, 23 Oct 2006 20:56:43 +0000 Subject: Re: [patch] Mixed Madison and Montecito system support Message-Id: <20061023205643.GA13990@intel.com> List-Id: References: <200610130325.k9D3PwIo17962445@clink.americas.sgi.com> In-Reply-To: <200610130325.k9D3PwIo17962445@clink.americas.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Russ Anderson Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Cc: linux-kernel for generic bit of this change. Rest of patch was posted to linux-ia64: http://marc.theaimsgroup.com/?l=linux-ia64&m6070997529216&w=2 On Thu, Oct 12, 2006 at 10:25:58PM -0500, Russ Anderson wrote: > int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) > { > - int err = 0; > + int err = 0, c; > > #ifdef CONFIG_SCHED_SMT > - if (smt_capable()) > - err = sysfs_create_file(&cls->kset.kobj, > + for_each_online_cpu(c) > + if (smt_capable(c)) { > + err = sysfs_create_file(&cls->kset.kobj, > &attr_sched_smt_power_savings.attr); > + break; > + } > #endif What if you booted an all-Madison system, and then hot-plugged some Montecitos later? Either we'd need the hotplug cpu code to run through this routine again to re-test whether any cpu has multi-thread support (it doesn't look like it does that now). Or perhaps it would be simpler to dispense with this test and always call sysfs_create_file() here (still inside CONFIG_SCHED_SMT) so that the hook is always present to tune the scheduler (even if it may be ineffective on a no-smt system)? -Tony