From: "Rafael J. Wysocki" <email@example.com> To: Doug Smythies <firstname.lastname@example.org> Cc: "'Rafael J. Wysocki'" <email@example.com>, 'Linux Documentation' <firstname.lastname@example.org>, 'LKML' <email@example.com>, 'Peter Zijlstra' <firstname.lastname@example.org>, 'Srinivas Pandruvada' <email@example.com>, 'Giovanni Gherdovich' <firstname.lastname@example.org>, 'Francisco Jerez' <email@example.com>, 'Linux PM' <firstname.lastname@example.org> Subject: Re: [PATCH] cpufreq: intel_pstate: Implement passive mode with HWP enabled Date: Thu, 06 Aug 2020 13:39:53 +0200 Message-ID: <5275102.Ez0hqPNOlg@kreacher> (raw) In-Reply-To: <004601d66bb6$199ce1a0$4cd6a4e0$@net> On Thursday, August 6, 2020 7:54:47 AM CEST Doug Smythies wrote: > On 2020.08.03 10:09 Rafael J. Wysocki wrote: > > On Sunday, August 2, 2020 5:17:39 PM CEST Doug Smythies wrote: > > > On 2020.07.19 04:43 Rafael J. Wysocki wrote: > > > > On Fri, Jul 17, 2020 at 3:37 PM Doug Smythies <email@example.com> wrote: > > > > > On 2020.07.16 05:08 Rafael J. Wysocki wrote: > > > > > > On Wed, Jul 15, 2020 at 10:39 PM Doug Smythies <firstname.lastname@example.org> wrote: > > > > > >> On 2020.07.14 11:16 Rafael J. Wysocki wrote: > > > > > >> > > > > > > >> > From: Rafael J. Wysocki <email@example.com> > > > > > >> ... > > > > > >> > Since the passive mode hasn't worked with HWP at all, and it is not going to > > > > > >> > the default for HWP systems anyway, I don't see any drawbacks related to making > > > > > >> > this change, so I would consider this as 5.9 material unless there are any > > > > > >> > serious objections. > > > > > >> > > > > > >> Good point. > > > > > > > > > > Actually, for those users that default to passive mode upon boot, > > > > > this would mean they would find themselves using this. > > > > > Also, it isn't obvious, from the typical "what driver and what governor" > > > > > inquiry. > > > > > > > > So the change in behavior is that after this patch > > > > intel_pstate=passive doesn't imply no_hwp any more. > > > > > > > > That's a very minor difference though and I'm not aware of any adverse > > > > effects it can cause on HWP systems anyway. > > > > > > My point was, that it will now default to something where > > > testing has not been completed. > > > > > > > The "what governor" is straightforward in the passive mode: that's > > > > whatever cpufreq governor has been selected. > > > > > > I think you might have missed my point. > > > From the normal methods of inquiry one does not know > > > if HWP is being used or not. Why? Because with > > > or without HWP one gets the same answers under: > > > > > > /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver > > > /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor > > > > Yes, but this is also the case in the active mode, isn't it? > > Yes, fair enough. > But we aren't changing what it means by default > between kernel 5.8 and 5.9-rc1. No, we aren't. The only (expected) change is when booting with intel_pstate=passive and without intel_pstate=no_hwp in the command line. Which should be easy enough to address by adding intel_pstate=no_hwp to the command line in 5.9-rc1 and later (to achieve the same behavior after a fresh boot). Cheers!
prev parent reply index Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-14 18:16 Rafael J. Wysocki 2020-07-15 0:09 ` Francisco Jerez 2020-07-15 12:04 ` Rafael J. Wysocki 2020-07-15 21:35 ` Francisco Jerez 2020-07-16 1:14 ` Srinivas Pandruvada 2020-07-16 14:33 ` Rafael J. Wysocki 2020-07-16 14:32 ` Rafael J. Wysocki 2020-07-17 0:21 ` Francisco Jerez 2020-07-19 19:06 ` Rafael J. Wysocki 2020-07-20 23:20 ` Francisco Jerez 2020-07-21 16:25 ` Srinivas Pandruvada 2020-07-21 23:14 ` Francisco Jerez 2020-07-27 17:23 ` Rafael J. Wysocki 2020-07-27 17:15 ` Rafael J. Wysocki 2020-07-28 2:32 ` Francisco Jerez 2020-07-28 18:27 ` Rafael J. Wysocki 2020-07-29 5:46 ` Francisco Jerez 2020-07-29 17:52 ` Rafael J. Wysocki 2020-07-30 0:49 ` Francisco Jerez 2020-07-31 17:52 ` Rafael J. Wysocki 2020-07-31 22:43 ` Francisco Jerez 2020-07-28 15:41 ` Rafael J. Wysocki 2020-07-15 20:39 ` Doug Smythies 2020-07-16 12:07 ` Rafael J. Wysocki 2020-07-17 13:37 ` Doug Smythies 2020-07-19 11:42 ` Rafael J. Wysocki 2020-08-02 15:17 ` Doug Smythies 2020-08-03 17:08 ` Rafael J. Wysocki 2020-08-06 5:54 ` Doug Smythies 2020-08-06 11:39 ` Rafael J. Wysocki [this message]
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