Messages in this thread | | | Date | Mon, 5 Dec 2022 16:57:46 -0600 | Subject | Re: [PATCH] cpufreq: acpi: Defer setting boost MSRs | From | stuart hayes <> |
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On 12/5/2022 6:43 AM, Rafael J. Wysocki wrote: > On Sun, Dec 4, 2022 at 8:20 PM stuart hayes <stuart.w.hayes@gmail.com> wrote: >> >> >> >> On 12/4/2022 12:29 PM, Borislav Petkov wrote: >>> On Thu, Nov 03, 2022 at 07:19:47PM +0100, Rafael J. Wysocki wrote: >>>> On Wed, Nov 2, 2022 at 9:01 PM Stuart Hayes <stuart.w.hayes@gmail.com> wrote: >>>>> >>>>> When acpi-cpufreq is loaded, boost is enabled on every CPU (by setting an >>>>> MSR) before the driver is registered with cpufreq. This can be very time >>>>> consuming, because it is done with a CPU hotplug startup callback, and >>>>> cpuhp_setup_state() schedules the callback (cpufreq_boost_online()) to run >>>>> on each CPU one at a time, waiting for each to run before calling the next. >>>>> >>>>> If cpufreq_register_driver() fails--if, for example, there are no ACPI >>>>> P-states present--this is wasted time. >>>>> >>>>> Since cpufreq already sets up a CPU hotplug startup callback if and when >>>>> acpi-cpufreq is registered, set the boost MSRs in acpi_cpufreq_cpu_init(), >>>>> which is called by the cpufreq cpuhp callback. This allows acpi-cpufreq to >>>>> exit quickly if it is loaded but not needed. >>>>> >>>>> On one system with 192 CPUs, this patch speeds up boot by about 30 seconds. >>>>> >>>>> Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com> >>>>> --- >>>>> drivers/cpufreq/acpi-cpufreq.c | 31 +++---------------------------- >>>>> 1 file changed, 3 insertions(+), 28 deletions(-) >>> >>> ... >>> >>>> Applied as 6.2 material, thanks! >>> >>> My 32-bit Atom doesn't like this one. Reverting fixes it ofc. >>> >>> [ 22.780260] unchecked MSR access error: WRMSR to 0x1a0 (tried to write 0x0000004364950488) at rIP: 0xf80b37d4 (boost_set_msr.isra.0+0x9c/0x114 [acpi_cpufreq]) >>> [ 22.781186] Call Trace: >>> [ 22.781186] boost_set_msr_each+0x15/0x1c [acpi_cpufreq] >>> [ 22.781186] __flush_smp_call_function_queue+0x132/0x1cc >>> [ 22.781186] ? sysvec_call_function+0x30/0x30 >>> [ 22.781186] generic_smp_call_function_single_interrupt+0x12/0x18 >>> [ 22.781186] __sysvec_call_function_single.constprop.0+0x43/0x1d8 >>> [ 22.781186] sysvec_call_function_single+0x18/0x30 >>> [ 22.781186] handle_exception+0x133/0x133 >>> [ 22.781186] EIP: finish_task_switch.isra.0+0x124/0x3a8 >>> [ 22.781186] Code: d8 e8 8c 16 92 00 85 f6 75 e8 a1 04 24 6c c2 85 c0 0f 8f 9b 00 00 00 89 d8 e8 e4 02 92 00 e8 53 9e 0b 00 fb 64 a1 40 f9 69 c2 <8b> 80 5c 0f 00 00 85 c0 0f 85 72 01 00 00 a1 28 24 6c c2 64 8b 15 >>> [ 22.781186] EAX: c32e2700 EBX: f748af40 ECX: 00000000 EDX: c1c3876e >>> [ 22.781186] ESI: 00000000 EDI: 00000000 EBP: c3241f90 ESP: c3241f78 >>> [ 22.781186] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00000206 >>> [ 22.781186] ? uevent_seqnum_show+0x1b/0x28 >>> [ 22.781186] ? pid_list_refill_irq+0x128/0x1c0 >>> [ 22.781186] ? sysvec_call_function+0x30/0x30 >>> [ 22.781186] ? pid_list_refill_irq+0x128/0x1c0 >>> [ 22.781186] ? sysvec_call_function+0x30/0x30 >>> [ 22.781186] ? finish_task_switch.isra.0+0x124/0x3a8 >>> [ 22.781186] schedule_tail+0x12/0x78 >>> [ 22.781186] schedule_tail_wrapper+0x9/0x10 >>> [ 22.781186] ret_from_fork+0x5/0x28 >>> [ 22.781186] EIP: 0xb7fba549 >>> [ 22.781186] Code: Unable to access opcode bytes at 0xb7fba51f. >>> [ 22.781186] EAX: 00000000 EBX: 01200011 ECX: 00000000 EDX: 00000000 >>> [ 22.781186] ESI: 00000000 EDI: b7bfe868 EBP: 00000000 ESP: bfcfedc0 >>> [ 22.781186] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000246 >>> >> >> I believe I see the problem... acpi_cpufreq_cpu_init is calling set_boost() directly without checking to see if acpi_cpufreq_driver.set_boost was set, so it is trying to set the MSR on CPUs that don't support it. >> >> Thanks, I can submit a patch to fix this. > > Yes, please. > > Note that I need to get this fix shortly, though, or I will just > revert the problemating commit before the 6.2 merge window opens.
I sent it a few hours ago as "[PATCH] cpufreq: acpi: Only set boost MSRs on supported CPUs". Thanks!
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