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From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Amit Kucheria <amit.kucheria@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Linux PM <linux-pm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 00/28] PM: QoS: Get rid of unuseful code and rework CPU latency QoS interface
Date: Thu, 13 Feb 2020 11:22:41 +0100	[thread overview]
Message-ID: <CAJZ5v0g5+k3GRy+p-6GxmsbpVNiRwvWXZ+w7-Jhq53oxJpZCgw@mail.gmail.com> (raw)
In-Reply-To: <CAJZ5v0i5thgrdGNQ+a1tuw=CGa8PAhHt19GoDpC8KLLjNVoQLQ@mail.gmail.com>

On Thu, Feb 13, 2020 at 11:17 AM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> On Thu, Feb 13, 2020 at 8:10 AM Amit Kucheria <amit.kucheria@linaro.org> wrote:
> >
> > On Wed, Feb 12, 2020 at 5:09 AM Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> > >
> > > Hi All,
> > >
> > > This series of patches is based on the observation that after commit
> > > c3082a674f46 ("PM: QoS: Get rid of unused flags") the only global PM QoS class
> > > in use is PM_QOS_CPU_DMA_LATENCY, but there is still a significant amount of
> > > code dedicated to the handling of global PM QoS classes in general.  That code
> > > takes up space and adds overhead in vain, so it is better to get rid of it.
> > >
> > > Moreover, with that unuseful code removed, the interface for adding QoS
> > > requests for CPU latency becomes inelegant and confusing, so it is better to
> > > clean it up.
> > >
> > > Patches [01/28-12/28] do the first part described above, which also includes
> > > some assorted cleanups of the core PM QoS code that doesn't go away.
> > >
> > > Patches [13/28-25/28] rework the CPU latency QoS interface (in the classic
> > > "define stubs, migrate users, change the API proper" manner), patches
> > > [26-27/28] update the general comments and documentation to match the code
> > > after the previous changes and the last one makes the CPU latency QoS depend
> > > on CPU_IDLE (because cpuidle is the only user of its target value today).
> > >
> > > The majority of the patches in this series don't change the functionality of
> > > the code at all (at least not intentionally).
> > >
> > > Please refer to the changelogs of individual patches for details.
> >
> > Hi Rafael,
> >
> > Nice cleanup to the code and docs.
> >
> > I've reviewed the series, and briefly tested it by setting latencies
> > from userspace. Can we not remove the debugfs interface? It is a quick
> > way to check the global cpu latency clamp on the system from userspace
> > without setting up tracepoints or writing a program to read
> > /dev/cpu_dma_latency.
>
> Come on.
>
> What about in Python?
>
> #!/usr/bin/env python
> import numpy as np
>
> if __name__ == '__main__':
>     f = open("/dev/cpu_dma_latency", "r")
>     print(np.fromfile(f, dtype=np.int32, count=1))
>     f.close()
>
> And probably you can do it in at least 20 different ways. :-)
>
> Also note that "echo the_debugfs_thing" does the equivalent, but the

I obviously meant "cat the_debugfs_thing" here, sorry.

  reply	other threads:[~2020-02-13 10:22 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-11 22:51 Rafael J. Wysocki
2020-02-11 22:52 ` [PATCH 01/28] PM: QoS: Drop debugfs interface Rafael J. Wysocki
2020-02-11 22:58 ` [PATCH 02/28] PM: QoS: Drop pm_qos_update_request_timeout() Rafael J. Wysocki
2020-02-11 22:58 ` [PATCH 03/28] PM: QoS: Drop the PM_QOS_SUM QoS type Rafael J. Wysocki
2020-02-11 22:58 ` [PATCH 04/28] PM: QoS: Clean up pm_qos_update_target() and pm_qos_update_flags() Rafael J. Wysocki
2020-02-11 22:58 ` [PATCH 05/28] PM: QoS: Clean up pm_qos_read_value() and pm_qos_get/set_value() Rafael J. Wysocki
2020-02-11 22:59 ` [PATCH 06/28] PM: QoS: Drop iterations over global QoS classes Rafael J. Wysocki
2020-02-11 23:00 ` [PATCH 07/28] PM: QoS: Clean up misc device file operations Rafael J. Wysocki
2020-02-11 23:01 ` [PATCH 08/28] PM: QoS: Redefine struct pm_qos_request and drop struct pm_qos_object Rafael J. Wysocki
2020-02-11 23:02 ` [PATCH 09/28] PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY notifier chain Rafael J. Wysocki
2020-02-11 23:04 ` [PATCH 10/28] PM: QoS: Rename things related to the CPU latency QoS Rafael J. Wysocki
2020-02-12 10:34   ` Rafael J. Wysocki
2020-02-12 19:13   ` Greg Kroah-Hartman
2020-02-11 23:06 ` [PATCH 11/28] PM: QoS: Simplify definitions of CPU latency QoS trace events Rafael J. Wysocki
2020-02-11 23:07 ` [PATCH 12/28] PM: QoS: Adjust pm_qos_request() signature and reorder pm_qos.h Rafael J. Wysocki
2020-02-11 23:07 ` [PATCH 13/28] PM: QoS: Add CPU latency QoS API wrappers Rafael J. Wysocki
2020-02-11 23:08 ` [PATCH 14/28] cpuidle: Call cpu_latency_qos_limit() instead of pm_qos_request() Rafael J. Wysocki
2020-02-11 23:10 ` [PATCH 15/28] x86: platform: iosf_mbi: Call cpu_latency_qos_*() instead of pm_qos_*() Rafael J. Wysocki
2020-02-12 10:14   ` Andy Shevchenko
2020-02-11 23:12 ` [PATCH 16/28] drm: i915: " Rafael J. Wysocki
2020-02-11 23:12   ` [Intel-gfx] " Rafael J. Wysocki
2020-02-12 10:32   ` Rafael J. Wysocki
2020-02-12 10:32     ` [Intel-gfx] " Rafael J. Wysocki
2020-02-14  7:42   ` Jani Nikula
2020-02-14  7:42     ` [Intel-gfx] " Jani Nikula
2020-02-11 23:13 ` [PATCH 17/28] drivers: hsi: " Rafael J. Wysocki
2020-02-13 21:06   ` Sebastian Reichel
2020-02-11 23:17 ` [PATCH 18/28] drivers: media: " Rafael J. Wysocki
2020-02-12  5:37   ` Mauro Carvalho Chehab
2020-02-11 23:21 ` [PATCH 19/28] drivers: mmc: " Rafael J. Wysocki
2020-02-11 23:24 ` [PATCH 20/28] drivers: net: " Rafael J. Wysocki
2020-02-11 23:48   ` Jeff Kirsher
2020-02-12  5:49   ` Kalle Valo
2020-02-11 23:26 ` [PATCH 21/28] drivers: spi: " Rafael J. Wysocki
2020-02-11 23:26   ` Rafael J. Wysocki
2020-02-11 23:27 ` [PATCH 22/28] drivers: tty: " Rafael J. Wysocki
2020-02-12 10:35   ` Rafael J. Wysocki
2020-02-12 19:13   ` Greg Kroah-Hartman
2020-02-11 23:28 ` [PATCH 23/28] drivers: usb: " Rafael J. Wysocki
2020-02-12 18:38   ` Greg KH
2020-02-18  8:03     ` Peter Chen
2020-02-18  8:08       ` Greg KH
2020-02-18  8:11         ` Peter Chen
2020-02-19  1:09   ` Peter Chen
2020-02-11 23:34 ` [PATCH 24/28] sound: " Rafael J. Wysocki
2020-02-11 23:34   ` [alsa-devel] " Rafael J. Wysocki
2020-02-12 10:08   ` Mark Brown
2020-02-12 10:08     ` [alsa-devel] " Mark Brown
2020-02-12 10:16     ` Rafael J. Wysocki
2020-02-12 10:16       ` [alsa-devel] " Rafael J. Wysocki
2020-02-12 10:21       ` Takashi Iwai
2020-02-12 10:21         ` [alsa-devel] " Takashi Iwai
2020-02-12 10:18   ` Mark Brown
2020-02-12 10:18     ` [alsa-devel] " Mark Brown
2020-02-11 23:35 ` [PATCH 25/28] PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY and rename related functions Rafael J. Wysocki
2020-02-11 23:35 ` [PATCH 26/28] PM: QoS: Update file information comments Rafael J. Wysocki
2020-02-11 23:36 ` [PATCH 27/28] Documentation: PM: QoS: Update to reflect previous code changes Rafael J. Wysocki
2020-02-11 23:37 ` [PATCH 28/28] PM: QoS: Make CPU latency QoS depend on CONFIG_CPU_IDLE Rafael J. Wysocki
2020-02-12  8:37 ` [PATCH 00/28] PM: QoS: Get rid of unuseful code and rework CPU latency QoS interface Ulf Hansson
2020-02-12  9:17   ` Rafael J. Wysocki
2020-02-12  9:39 ` Rafael J. Wysocki
2020-02-12 23:32 ` Francisco Jerez
2020-02-13  0:16   ` Rafael J. Wysocki
2020-02-13  0:37     ` Rafael J. Wysocki
2020-02-13  8:10       ` Francisco Jerez
2020-02-13 11:38         ` Rafael J. Wysocki
2020-02-21 22:10           ` Francisco Jerez
2020-02-24  0:29             ` Rafael J. Wysocki
2020-02-24 21:06               ` Francisco Jerez
2020-02-13  8:07     ` Francisco Jerez
2020-02-13 11:34       ` Rafael J. Wysocki
2020-02-13 16:35         ` Rafael J. Wysocki
2020-02-14  0:15           ` Francisco Jerez
2020-02-14 10:42             ` Rafael J. Wysocki
2020-02-14 20:32               ` Francisco Jerez
2020-02-24 10:39                 ` Rafael J. Wysocki
2020-02-24 21:16                   ` Francisco Jerez
2020-02-14  0:14         ` Francisco Jerez
2020-02-13  7:10 ` Amit Kucheria
2020-02-13 10:17   ` Rafael J. Wysocki
2020-02-13 10:22     ` Rafael J. Wysocki [this message]
2020-02-13 10:49     ` Amit Kucheria
2020-02-13 11:36       ` Rafael J. Wysocki

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