> -----Original Message----- > From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi- > owner@xxxxxxxxxxxxxxx] On Behalf Of Rafael J. Wysocki > Sent: Thursday, October 07, 2010 2:44 PM > To: Greg KH > Cc: Sameer Nanda; lenb@xxxxxxxxxx; stefan.bader@xxxxxxxxxxxxx; > brad.figg@xxxxxxxxxxxxx; apw@xxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] ACPI: Read TSC upon resume > > On Thursday, October 07, 2010, Greg KH wrote: > > On Thu, Oct 07, 2010 at 11:05:21AM -0700, Sameer Nanda wrote: > > > On Thu, Oct 7, 2010 at 10:46 AM, Greg KH <gregkh@xxxxxxx> wrote: > > > > On Thu, Oct 07, 2010 at 10:43:34AM -0700, Sameer Nanda wrote: > > > >> On Wed, Oct 6, 2010 at 7:19 PM, Greg KH <gregkh@xxxxxxx> wrote: > > > >> > And are you always going to be printing this out? Why do we > want to > > > >> > know this every time? > > > >> > > > > >> > > > >> Yes, every time. This helps track variance in BIOS resume times > within a > > > >> single boot. > > > > > > > > Is that really something that users can do something about? > > > > > > Aside from complaining to the BIOS vendors, no :) > > > > Then I would not recommend adding this patch, as it is irrelevant for > > 99.9999% of all Linux users. > > It may be somewhat useful, but the rdtscll() call seems to be x86- > specific, in > which case it shouldn't be used at this place. Also, in the case of an intel core 2 duo cpu, the tsc is not stable, hence upon resume the cpu is spinning up and the first tsc's will be slower. During idle-time the tsc will not be incremented. The tsc is only stably incremented upon 100% cpu usage. It also doesn't increment faster in turbo mode in case of some core 2 duo and certainly the Nehalem cpu's. Calculating in time in terms of tsc might not be so reliable. > > Thanks, > Rafael > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" > in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
