Re: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive
On Mon, 06 Jul 2020 01:15:42 PDT (-0700), sch...@suse.de wrote:
On Jul 03 2020, Yash Shah wrote:
Yes, you are right. The userspace governor is the only one supported.
That doesn't make sense to me. How is the userspace governor different
from any other governor?
It's not.
The issue here is that pretty much everything is on one clock, including all
the cores and the simple IO devices. These IO devices have programmable clock
dividers that need to mesh up with the input clock rate in order to operate
correctly. There's no way to do that atomicly WRT the device's clock, so we
have to pause device IO while messing with the clocks.
I bet there's some issue with 4cbd7814bbd5 ("tty: sifive: Finish transmission
before changing the clock") that's causing the serial to get corrupted, and I
guess I'd start with all the issues I pointed out in the patch text :).
Presumably we need to fix the SPI driver as well, in much the same fashion
(though hopefully with fewer hardware surprises to work around). I'd be way
more worried about ChipLink, as I don't know how that's clocked. IIRC Ethernet
has its own clock so it should be safe.
I'd be very skeptical about turning on dynamic frequency scaling for the HiFive
Unleashed, as it's probably just not worth chasing the long tail of bugs. Even
allowing the userspace governor is a bit sketchy, but given that it's a very
early dev board I assume these sorts of problems are expected.
If we do ever turn dynamic frequency scaling on it's not going to default to
allowing 1.4GHz, from what I saw speeds much over 1GHz don't work for most
people.
RE: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive
Hi Andreas, > -Original Message- > From: Andreas Schwab > Sent: 01 July 2020 16:11 > To: Yash Shah > Cc: Paul Walmsley ( Sifive) ; > pal...@dabbelt.com; robh...@kernel.org; linux-ri...@lists.infradead.org; > linux-kernel@vger.kernel.org; devicet...@vger.kernel.org; Sachin Ghadi > ; a...@eecs.berkeley.edu; a...@brainfault.org; > lolliv...@baylibre.com; Green Wan ; > atish.pa...@wdc.com; alistair.fran...@wdc.com; deepa.ker...@gmail.com; > bmeng...@gmail.com > Subject: Re: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive > > [External Email] Do not click links or attachments unless you recognize the > sender and know the content is safe > > On Jun 16 2020, Yash Shah wrote: > > > The patch series adds the support for dynamic CPU frequency switching > > for FU540-C000 SoC on the HiFive Unleashed board. All the patches are > > based on Paul Walmsley's work. > > > > This series is based on Linux v5.7 and tested on HiFive unleashed board. > > I'm using that patch with 5.7.5. > > It appears to interfer with serial output when using the ondemand governor. > > I also see soft lockups when using the performance governor: > > [ 101.587527] rcu: INFO: rcu_sched self-detected stall on CPU > [ 101.592322] rcu: 0-...!: (932 ticks this GP) > idle=11a/1/0x4004 softirq=4301/4301 fqs=4 > [ 101.601432] (t=6001 jiffies g=4017 q=859) [ 101.605514] rcu: rcu_sched > kthread starved for 5984 jiffies! g4017 f0x0 RCU_GP_WAIT_FQS(5) - > >state=0x0 ->cpu=2 [ 101.615494] rcu: RCU grace-period kthread stack > dump: > [ 101.620530] rcu_sched R running task010 2 > 0x > [ 101.627560] Call Trace: > [ 101.630004] [] __schedule+0x25c/0x616 [ 101.635205] > [] schedule+0x42/0xb2 [ 101.640070] > [] schedule_timeout+0x56/0xb8 [ 101.645626] > [] rcu_gp_fqs_loop+0x208/0x248 [ 101.651266] > [] rcu_gp_kthread+0xc2/0xcc [ 101.656651] > [] kthread+0xda/0xec [ 101.661426] [] > ret_from_exception+0x0/0xc [ 101.666977] Task dump for CPU 0: > [ 101.670187] loop0 R running task0 655 2 > 0x0008 > [ 101.677218] Call Trace: > [ 101.679657] [] walk_stackframe+0x0/0xaa [ > 101.685036] [] show_stack+0x2a/0x34 [ 101.690074] > [] sched_show_task.part.0+0xc2/0xd2 [ 101.696154] > [] sched_show_task+0x64/0x66 [ 101.701618] > [] dump_cpu_task+0x3e/0x48 [ 101.706916] > [] rcu_dump_cpu_stacks+0x94/0xce [ 101.712731] > [] print_cpu_stall+0x116/0x18a [ 101.718375] > [] check_cpu_stall+0xcc/0x1a2 [ 101.723929] > [] rcu_pending.constprop.0+0x36/0xaa [ 101.730094] > [] rcu_sched_clock_irq+0xa6/0xea [ 101.735913] > [] update_process_times+0x1e/0x42 [ 101.741821] > [] tick_sched_handle+0x26/0x52 [ 101.747456] > [] tick_sched_timer+0x6a/0xd0 [ 101.753015] > [] __run_hrtimer.constprop.0+0x50/0xe8 > [ 101.759353] [] __hrtimer_run_queues+0x48/0x6c [ > 101.765254] [] hrtimer_interrupt+0xca/0x1d4 [ > 101.770985] [] riscv_timer_interrupt+0x32/0x3a [ > 101.776976] [] do_IRQ+0xa4/0xb8 [ 101.781663] > [] ret_from_exception+0x0/0xc > > Andreas. > > -- > Andreas Schwab, SUSE Labs, sch...@suse.de GPG Key fingerprint = 0196 > BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 "And now for something > completely different." I am looking into the issues you reported. I will update soon. Thanks for testing. - Yash
Re: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive
On Jul 03 2020, Yash Shah wrote: > Yes, you are right. The userspace governor is the only one supported. That doesn't make sense to me. How is the userspace governor different from any other governor? Andreas. -- Andreas Schwab, SUSE Labs, sch...@suse.de GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 "And now for something completely different."
RE: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive
> -Original Message- > From: David Abdurachmanov > Sent: 01 July 2020 17:34 > To: Andreas Schwab > Cc: Yash Shah ; devicet...@vger.kernel.org; Albert > Ou ; Atish Patra ; Anup > Patel ; lolliv...@baylibre.com; linux- > ker...@vger.kernel.org List ; Green Wan > ; Sachin Ghadi ; > robh...@kernel.org; Palmer Dabbelt ; > deepa.ker...@gmail.com; Paul Walmsley ( Sifive) > ; Alistair Francis ; > linux-riscv ; Bin Meng > > Subject: Re: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive > > [External Email] Do not click links or attachments unless you recognize the > sender and know the content is safe > > On Wed, Jul 1, 2020 at 1:41 PM Andreas Schwab wrote: > > > > On Jun 16 2020, Yash Shah wrote: > > > > > The patch series adds the support for dynamic CPU frequency > > > switching for FU540-C000 SoC on the HiFive Unleashed board. All the > > > patches are based on Paul Walmsley's work. > > > > > > This series is based on Linux v5.7 and tested on HiFive unleashed board. > > > > I'm using that patch with 5.7.5. > > > > It appears to interfer with serial output when using the ondemand > > governor. > > I do recall that userspace governor is the only one supported but this might > have changed before this patch was posted. > > Yash, do you have more details? Yes, you are right. The userspace governor is the only one supported. - Yash > > > > > I also see soft lockups when using the performance governor: > > > > [ 101.587527] rcu: INFO: rcu_sched self-detected stall on CPU > > [ 101.592322] rcu: 0-...!: (932 ticks this GP) > idle=11a/1/0x4004 softirq=4301/4301 fqs=4 > > [ 101.601432] (t=6001 jiffies g=4017 q=859) [ 101.605514] rcu: > > rcu_sched kthread starved for 5984 jiffies! g4017 f0x0 > > RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=2 [ 101.615494] rcu: RCU grace- > period kthread stack dump: > > [ 101.620530] rcu_sched R running task010 2 > > 0x > > [ 101.627560] Call Trace: > > [ 101.630004] [] __schedule+0x25c/0x616 [ > > 101.635205] [] schedule+0x42/0xb2 [ 101.640070] > > [] schedule_timeout+0x56/0xb8 [ 101.645626] > > [] rcu_gp_fqs_loop+0x208/0x248 [ 101.651266] > > [] rcu_gp_kthread+0xc2/0xcc [ 101.656651] > > [] kthread+0xda/0xec [ 101.661426] > > [] ret_from_exception+0x0/0xc [ 101.666977] Task > > dump for CPU 0: > > [ 101.670187] loop0 R running task0 655 2 > > 0x0008 > > [ 101.677218] Call Trace: > > [ 101.679657] [] walk_stackframe+0x0/0xaa [ > > 101.685036] [] show_stack+0x2a/0x34 [ 101.690074] > > [] sched_show_task.part.0+0xc2/0xd2 [ 101.696154] > > [] sched_show_task+0x64/0x66 [ 101.701618] > > [] dump_cpu_task+0x3e/0x48 [ 101.706916] > > [] rcu_dump_cpu_stacks+0x94/0xce [ 101.712731] > > [] print_cpu_stall+0x116/0x18a [ 101.718375] > > [] check_cpu_stall+0xcc/0x1a2 [ 101.723929] > > [] rcu_pending.constprop.0+0x36/0xaa [ 101.730094] > > [] rcu_sched_clock_irq+0xa6/0xea [ 101.735913] > > [] update_process_times+0x1e/0x42 [ 101.741821] > > [] tick_sched_handle+0x26/0x52 [ 101.747456] > > [] tick_sched_timer+0x6a/0xd0 [ 101.753015] > > [] __run_hrtimer.constprop.0+0x50/0xe8 > > [ 101.759353] [] __hrtimer_run_queues+0x48/0x6c [ > > 101.765254] [] hrtimer_interrupt+0xca/0x1d4 [ > > 101.770985] [] riscv_timer_interrupt+0x32/0x3a [ > > 101.776976] [] do_IRQ+0xa4/0xb8 [ 101.781663] > > [] ret_from_exception+0x0/0xc > > > > Andreas. > > > > -- > > Andreas Schwab, SUSE Labs, sch...@suse.de GPG Key fingerprint = 0196 > > BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 "And now for something > > completely different." > > > > ___ > > linux-riscv mailing list > > linux-ri...@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-riscv
Re: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive
On Wed, Jul 1, 2020 at 1:41 PM Andreas Schwab wrote: > > On Jun 16 2020, Yash Shah wrote: > > > The patch series adds the support for dynamic CPU frequency switching > > for FU540-C000 SoC on the HiFive Unleashed board. All the patches are > > based on Paul Walmsley's work. > > > > This series is based on Linux v5.7 and tested on HiFive unleashed board. > > I'm using that patch with 5.7.5. > > It appears to interfer with serial output when using the ondemand > governor. I do recall that userspace governor is the only one supported but this might have changed before this patch was posted. Yash, do you have more details? > > I also see soft lockups when using the performance governor: > > [ 101.587527] rcu: INFO: rcu_sched self-detected stall on CPU > [ 101.592322] rcu: 0-...!: (932 ticks this GP) > idle=11a/1/0x4004 softirq=4301/4301 fqs=4 > [ 101.601432] (t=6001 jiffies g=4017 q=859) > [ 101.605514] rcu: rcu_sched kthread starved for 5984 jiffies! g4017 f0x0 > RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=2 > [ 101.615494] rcu: RCU grace-period kthread stack dump: > [ 101.620530] rcu_sched R running task010 2 > 0x > [ 101.627560] Call Trace: > [ 101.630004] [] __schedule+0x25c/0x616 > [ 101.635205] [] schedule+0x42/0xb2 > [ 101.640070] [] schedule_timeout+0x56/0xb8 > [ 101.645626] [] rcu_gp_fqs_loop+0x208/0x248 > [ 101.651266] [] rcu_gp_kthread+0xc2/0xcc > [ 101.656651] [] kthread+0xda/0xec > [ 101.661426] [] ret_from_exception+0x0/0xc > [ 101.666977] Task dump for CPU 0: > [ 101.670187] loop0 R running task0 655 2 > 0x0008 > [ 101.677218] Call Trace: > [ 101.679657] [] walk_stackframe+0x0/0xaa > [ 101.685036] [] show_stack+0x2a/0x34 > [ 101.690074] [] sched_show_task.part.0+0xc2/0xd2 > [ 101.696154] [] sched_show_task+0x64/0x66 > [ 101.701618] [] dump_cpu_task+0x3e/0x48 > [ 101.706916] [] rcu_dump_cpu_stacks+0x94/0xce > [ 101.712731] [] print_cpu_stall+0x116/0x18a > [ 101.718375] [] check_cpu_stall+0xcc/0x1a2 > [ 101.723929] [] rcu_pending.constprop.0+0x36/0xaa > [ 101.730094] [] rcu_sched_clock_irq+0xa6/0xea > [ 101.735913] [] update_process_times+0x1e/0x42 > [ 101.741821] [] tick_sched_handle+0x26/0x52 > [ 101.747456] [] tick_sched_timer+0x6a/0xd0 > [ 101.753015] [] __run_hrtimer.constprop.0+0x50/0xe8 > [ 101.759353] [] __hrtimer_run_queues+0x48/0x6c > [ 101.765254] [] hrtimer_interrupt+0xca/0x1d4 > [ 101.770985] [] riscv_timer_interrupt+0x32/0x3a > [ 101.776976] [] do_IRQ+0xa4/0xb8 > [ 101.781663] [] ret_from_exception+0x0/0xc > > Andreas. > > -- > Andreas Schwab, SUSE Labs, sch...@suse.de > GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 > "And now for something completely different." > > ___ > linux-riscv mailing list > linux-ri...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
Re: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive
On Jun 16 2020, Yash Shah wrote: > The patch series adds the support for dynamic CPU frequency switching > for FU540-C000 SoC on the HiFive Unleashed board. All the patches are > based on Paul Walmsley's work. > > This series is based on Linux v5.7 and tested on HiFive unleashed board. I'm using that patch with 5.7.5. It appears to interfer with serial output when using the ondemand governor. I also see soft lockups when using the performance governor: [ 101.587527] rcu: INFO: rcu_sched self-detected stall on CPU [ 101.592322] rcu: 0-...!: (932 ticks this GP) idle=11a/1/0x4004 softirq=4301/4301 fqs=4 [ 101.601432] (t=6001 jiffies g=4017 q=859) [ 101.605514] rcu: rcu_sched kthread starved for 5984 jiffies! g4017 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=2 [ 101.615494] rcu: RCU grace-period kthread stack dump: [ 101.620530] rcu_sched R running task010 2 0x [ 101.627560] Call Trace: [ 101.630004] [] __schedule+0x25c/0x616 [ 101.635205] [] schedule+0x42/0xb2 [ 101.640070] [] schedule_timeout+0x56/0xb8 [ 101.645626] [] rcu_gp_fqs_loop+0x208/0x248 [ 101.651266] [] rcu_gp_kthread+0xc2/0xcc [ 101.656651] [] kthread+0xda/0xec [ 101.661426] [] ret_from_exception+0x0/0xc [ 101.666977] Task dump for CPU 0: [ 101.670187] loop0 R running task0 655 2 0x0008 [ 101.677218] Call Trace: [ 101.679657] [] walk_stackframe+0x0/0xaa [ 101.685036] [] show_stack+0x2a/0x34 [ 101.690074] [] sched_show_task.part.0+0xc2/0xd2 [ 101.696154] [] sched_show_task+0x64/0x66 [ 101.701618] [] dump_cpu_task+0x3e/0x48 [ 101.706916] [] rcu_dump_cpu_stacks+0x94/0xce [ 101.712731] [] print_cpu_stall+0x116/0x18a [ 101.718375] [] check_cpu_stall+0xcc/0x1a2 [ 101.723929] [] rcu_pending.constprop.0+0x36/0xaa [ 101.730094] [] rcu_sched_clock_irq+0xa6/0xea [ 101.735913] [] update_process_times+0x1e/0x42 [ 101.741821] [] tick_sched_handle+0x26/0x52 [ 101.747456] [] tick_sched_timer+0x6a/0xd0 [ 101.753015] [] __run_hrtimer.constprop.0+0x50/0xe8 [ 101.759353] [] __hrtimer_run_queues+0x48/0x6c [ 101.765254] [] hrtimer_interrupt+0xca/0x1d4 [ 101.770985] [] riscv_timer_interrupt+0x32/0x3a [ 101.776976] [] do_IRQ+0xa4/0xb8 [ 101.781663] [] ret_from_exception+0x0/0xc Andreas. -- Andreas Schwab, SUSE Labs, sch...@suse.de GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 "And now for something completely different."
Re: [PATCH 0/3] Dynamic CPU frequency switching for the HiFive
Yash Shah 於 2020年6月16日 週二 下午8:01寫道： > > The patch series adds the support for dynamic CPU frequency switching > for FU540-C000 SoC on the HiFive Unleashed board. All the patches are > based on Paul Walmsley's work. > > This series is based on Linux v5.7 and tested on HiFive unleashed board. > > Yash Shah (3): > riscv: defconfig, Kconfig: enable CPU power management > riscv: dts: fu540-c000: define hart clocks > riscv: dts: HiFive Unleashed: define a default set of CPU OPPs > > arch/riscv/Kconfig | 8 + > arch/riscv/boot/dts/sifive/fu540-c000.dtsi | 5 +++ > .../riscv/boot/dts/sifive/hifive-unleashed-a00.dts | 38 > ++ > arch/riscv/configs/defconfig | 5 +++ > 4 files changed, 56 insertions(+) > Hi Yash, Thank you for the patch. It works for me to test with cpufreq-ljt-stress-test. Here is my log. CPU stress test, which is doing JPEG decoding by libjpeg-turbo at different cpufreq operating points. Testing CPU 0 1400 MHz OK 999 MHz OK 700 MHz OK 350 MHz OK Testing CPU 1 1400 MHz OK 999 MHz OK 700 MHz OK 350 MHz OK Testing CPU 2 1400 MHz OK 999 MHz OK 700 MHz OK 350 MHz OK Testing CPU 3 1400 MHz OK 999 MHz OK 700 MHz OK 350 MHz OK Overall result : PASSED Tested-by: Greentime Hu
[PATCH 0/3] Dynamic CPU frequency switching for the HiFive
The patch series adds the support for dynamic CPU frequency switching for FU540-C000 SoC on the HiFive Unleashed board. All the patches are based on Paul Walmsley's work. This series is based on Linux v5.7 and tested on HiFive unleashed board. Yash Shah (3): riscv: defconfig, Kconfig: enable CPU power management riscv: dts: fu540-c000: define hart clocks riscv: dts: HiFive Unleashed: define a default set of CPU OPPs arch/riscv/Kconfig | 8 + arch/riscv/boot/dts/sifive/fu540-c000.dtsi | 5 +++ .../riscv/boot/dts/sifive/hifive-unleashed-a00.dts | 38 ++ arch/riscv/configs/defconfig | 5 +++ 4 files changed, 56 insertions(+) -- 2.7.4
