Re: arm64 board boot pauses on linux-next (resend)

[John Garry <john.garry@huawei.com>]

On 12/12/2018 17:17, Robin Murphy wrote:
> [ +Suzuki ]
>
> Hi John,
>

Hi Robin,

> On 12/12/2018 16:48, John Garry wrote:
>> Hi all,
>>
>> I am finding our arm64 D05 board particularly slow to boot from
>> linux-next, specifically a 30+ second pause when setting up CPU features.
>
> That does look like it's almost certainly spending the mystery time in
> setup_cpu_features() itself.

Seems to be "Kernel page table isolation (KPTI)" feature which we hang 
on, but I would not say that's conclusive.

>
>> I tried to bisect, but I am finding bisect holes (board does not boot
>> at all).
>
> I'd suggest focusing on the arm64 for-next/core branch, since we have
> some cpufeature rework queued there which was supposed to make it go
> quicker...

Tip of this branch doesn't exhibit the issue.

Cheers,
John

>
> Robin.
>
>>
>> Snippet good, like v4.20-rc6:
>> [    5.482756] smp: Brought up 4 nodes, 64 CPUs
>> [    7.423242] SMP: Total of 64 processors activated.
>> [    7.428087] CPU features: detected: GIC system register CPU interface
>> [    7.434620] CPU features: detected: 32-bit EL0 Support
>> [    7.439813] CPU features: detected: CRC32 instructions
>> [    7.530336] CPU: All CPU(s) started at EL2
>> [    7.534599] alternatives: patching kernel code
>> [    7.556042] devtmpfs: initialized
>> [    7.559982] clocksource: jiffies: mask: 0xffffffff max_cycles:
>> 0xffffffff, max_idle_ns: 7645041785100000 ns
>> [    7.569991] futex hash table entries: 16384 (order: 8, 1048576 bytes)
>> [    7.577262] pinctrl core: initialized pinctrl subsystem
>> [    7.582947] SMBIOS 3.0.0 present.
>> [    7.586293] DMI: Huawei Taishan 2280 /D05, BIOS Hisilicon D05 IT17
>> Nemo 2.0 RC0 10/05/2018
>> [    7.594812] NET: Registered protocol family 16
>> [    7.600073] audit: initializing netlink subsys (disabled)
>> [    7.605593] audit: type=2000 audit(5.072:1): state=initialized
>> audit_enabled=0 res=1
>>
>>
>> Snippet next-20181211:
>> [    5.483420] GICv3: CPU63: found redistributor 70303 region
>> 63:0x000004006d4c0000
>> [    5.483438] GICv3: CPU63: using allocated LPI pending table
>> @0x0000001fb8dd0000
>> [    5.483578] arch_timer: CPU63: Trapping CNTVCT access
>> [    5.483582] CPU63: Booted secondary processor 0x0000070303
>> [0x410fd082]
>> [    5.483666] smp: Brought up 4 nodes, 64 CPUs
>> [    7.424162] SMP: Total of 64 processors activated.
>> [    7.429006] CPU features: detected: GIC system register CPU interface
>> [    7.435538] CPU features: detected: 32-bit EL0 Support
>> [    7.440731] CPU features: detected: CRC32 instructions
>> [   40.107984] CPU: All CPU(s) started at EL2
>> [   40.112264] alternatives: patching kernel code
>> [   40.134299] devtmpfs: initialized
>> [   40.138196] clocksource: jiffies: mask: 0xffffffff max_cycles:
>> 0xffffffff, max_idle_ns: 7645041785100000 ns
>> [   40.148209] futex hash table entries: 16384 (order: 8, 1048576 bytes)
>> [   40.155486] pinctrl core: initialized pinctrl subsystem
>> [   40.161109] SMBIOS 3.0.0 present.
>> [   40.164456] DMI: Huawei Taishan 2280 /D05, BIOS Hisilicon D05 IT17
>> Nemo 2.0 RC0 10/05/2018
>> [   40.172985] NET: Registered protocol family 16
>> [   40.178236] audit: initializing netlink subsys (disabled)
>> [   40.183748] audit: type=2000 audit(5.072:1): state=initialized
>> audit_enabled=0 res=1
>>
>> Anyone else notice a similar issue?
>>
>> Our nextgen D06 board does not seem to have this issue.
>>
>> Thanks,
>> John
>>
>>
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>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
> .
>



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