[PATCH v7 3/7] cpufreq/schedutil: Use a fixed reference frequency

[Vincent Guittot]

Hi Mark,

Could you tried this fix:
https://lore.kernel.org/lkml/20240117190545.596057-1-vincent.guittot@linaro.org/

Regards,
Vincent

On Tue, 23 Jan 2024 at 02:55, Mark Brown <broonie at kernel.org> wrote:
>
> On Mon, Dec 11, 2023 at 11:48:51AM +0100, Vincent Guittot wrote:
> > cpuinfo.max_freq can change at runtime because of boost as an example. This
> > implies that the value could be different than the one that has been
> > used when computing the capacity of a CPU.
>
> So, this seems very weird but I just finished a bisection of a failure
> that showed up during the merge window with the DT kselftests on
> meson-gxl-s905x-libretech-cc (Libretech Le Potato) running an arm64
> defconfig.  Looking at the commit this seems like a very surprising
> false result but I verified that the commit before this one runs fine
> and reproduced the failure, the bisect does seem to converge well also
> so it appears like there's something going on.  Does this ring any bells
> for anyone?
>
> The test is timed out by the kselftest wrapper:
>
>    kselftest: Running tests in dt
>    TAP version 13
>    1..1
>    # timeout set to 45
>    # selftests: dt: test_unprobed_devices.sh
>    # TAP version 13
>    #
>    not ok 1 selftests: dt: test_unprobed_devices.sh # TIMEOUT 45 seconds
>
> with no obvious effect on the system, a successful run takes less than
> 20 seconds so it shouldn't be that the timing is marginal.  I'm guessing
> that reading the one of the files under /sys/devices hung.  No other
> boards in my lab are affected and I'm not immediately seeing anything
> remarkable about this board.  Full log from a bad run at:
>
>     https://lava.sirena.org.uk/scheduler/job/493329
>
> and a good run:
>
>     https://lava.sirena.org.uk/scheduler/job/492453
>
> Bisect log (the skipped commits didn't build):
>
> git bisect start
> # status: waiting for both good and bad commits
> # bad: [4fbbed7872677b0a28ba8237169968171a61efbd] Merge tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
> git bisect bad 4fbbed7872677b0a28ba8237169968171a61efbd
> # status: waiting for good commit(s), bad commit known
> # good: [0dd3ee31125508cd67f7e7172247f05b7fd1753a] Linux 6.7
> git bisect good 0dd3ee31125508cd67f7e7172247f05b7fd1753a
> # bad: [ba5afb9a84df2e6b26a1b6389b98849cd16ea757] fs: rework listmount() implementation
> git bisect bad ba5afb9a84df2e6b26a1b6389b98849cd16ea757
> # bad: [de927f6c0b07d9e698416c5b287c521b07694cac] Merge tag 's390-6.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
> git bisect bad de927f6c0b07d9e698416c5b287c521b07694cac
> # bad: [35f11a3710cdcbbc5090d14017a6295454e0cc73] Merge tag 'mtd/for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux
> git bisect bad 35f11a3710cdcbbc5090d14017a6295454e0cc73
> # bad: [d30e51aa7b1f6fa7dd78d4598d1e4c047fcc3fb9] Merge tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
> git bisect bad d30e51aa7b1f6fa7dd78d4598d1e4c047fcc3fb9
> # skip: [968b80332432172dbbb773e749a43bdc846d1a13] Merge tag 'powerpc-6.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
> git bisect skip 968b80332432172dbbb773e749a43bdc846d1a13
> # good: [372a34e66fb7f95124fadae9c600b231c35696a7] fs: replace f_rcuhead with f_task_work
> git bisect good 372a34e66fb7f95124fadae9c600b231c35696a7
> # good: [ae24db43b3b427eb290b58d55179c32f0a7539d1] powerpc/ftrace: Remove nops after the call to ftrace_stub
> git bisect good ae24db43b3b427eb290b58d55179c32f0a7539d1
> # skip: [3cf1d6a5fbf3f724d12b01635319924239d42c00] Merge tag 'm68k-for-v6.8-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k
> git bisect skip 3cf1d6a5fbf3f724d12b01635319924239d42c00
> # good: [2a33e2ddc6ebf9b5468091aded8a38f57de9a580] splice: remove permission hook from do_splice_direct()
> git bisect good 2a33e2ddc6ebf9b5468091aded8a38f57de9a580
> # good: [9b7e9e2f5d5c3d079ec46bc71b114012e362ea6e] fs: factor out backing_file_splice_{read,write}() helpers
> git bisect good 9b7e9e2f5d5c3d079ec46bc71b114012e362ea6e
> # good: [12c1b632d970c0138b4c5c65a1065e7d0604d272] fs: reformat idmapped mounts entry
> git bisect good 12c1b632d970c0138b4c5c65a1065e7d0604d272
> # good: [d23627a7688fabff0096a7beaff1a93de76afaad] EDAC/igen6: Add Intel Raptor Lake-P SoCs support
> git bisect good d23627a7688fabff0096a7beaff1a93de76afaad
> # skip: [ab5f3fcb7c72094684760e0cd8954d8d570b5e83] Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
> git bisect skip ab5f3fcb7c72094684760e0cd8954d8d570b5e83
> # good: [eb183b2cd0a6549992eca3c4ada0b1bc1d9340f5] Revert "perf/arm_dmc620: Remove duplicate format attribute #defines"
> git bisect good eb183b2cd0a6549992eca3c4ada0b1bc1d9340f5
> # good: [1ab33c03145d0f6c345823fc2da935d9a1a9e9fc] asm-generic: make sparse happy with odd-sized put_unaligned_*()
> git bisect good 1ab33c03145d0f6c345823fc2da935d9a1a9e9fc
> # good: [794c68b20408bb6899f90314e36e256924cc85a1] x86/CPU/AMD: Get rid of amd_erratum_1485[]
> git bisect good 794c68b20408bb6899f90314e36e256924cc85a1
> # bad: [11137d384996bb05cf33c8163db271e1bac3f4bf] sched/fair: Simplify util_est
> git bisect bad 11137d384996bb05cf33c8163db271e1bac3f4bf
> # good: [9c0b4bb7f6303c9c4e2e34984c46f5a86478f84d] sched/cpufreq: Rework schedutil governor performance estimation
> git bisect good 9c0b4bb7f6303c9c4e2e34984c46f5a86478f84d
> # good: [599457ba15403037b489fe536266a3d5f9efaed7] cpufreq: Use the fixed and coherent frequency for scaling capacity
> git bisect good 599457ba15403037b489fe536266a3d5f9efaed7
> # bad: [50b813b147e9eb6546a1fc49d4e703e6d23691f2] cpufreq/cppc: Move and rename cppc_cpufreq_{perf_to_khz|khz_to_perf}()
> git bisect bad 50b813b147e9eb6546a1fc49d4e703e6d23691f2
> # bad: [15cbbd1d317e07b4e5c6aca5d4c5579539a82784] energy_model: Use a fixed reference frequency
> git bisect bad 15cbbd1d317e07b4e5c6aca5d4c5579539a82784
> # bad: [b3edde44e5d4504c23a176819865cd603fd16d6c] cpufreq/schedutil: Use a fixed reference frequency
> git bisect bad b3edde44e5d4504c23a176819865cd603fd16d6c
> # first bad commit: [b3edde44e5d4504c23a176819865cd603fd16d6c] cpufreq/schedutil: Use a fixed reference frequency