Re: [RFC PATCH v1] x86/cpu: initialize the CPU concurrently

[Zhenyu Ye]

Hi Igor Mammedov,

Thanks for your review.

On 2020/12/19 1:17, Igor Mammedov wrote:
> On Wed, 25 Nov 2020 19:54:17 +0800
> Zhenyu Ye <yezhenyu2@huawei.com> wrote:
> 
>> From 0b4318c9dbf6fa152ec14eab29837ea06e2d78e5 Mon Sep 17 00:00:00 2001
>> From: eillon <yezhenyu2@huawei.com>
>> Date: Wed, 25 Nov 2020 19:17:03 +0800
>> Subject: [PATCH] x86/cpu: initialize the CPU concurrently
>>
>> Currently we initialize cpu one by one in qemu_init_vcpu(), every cpu
>> should have to wait util cpu->created = true.  When 
>> cpus_accel->create_vcpu_thread
>> costs too long time or the number of CPUs is too large, this will prolong
>> the boot time.
>>
>> This patch initializes the CPU concurrently.
> 
> could you benchmark and share results for before an after this patch?
> (It would be even better to add it as part of commit message)
> 

When using haxm as the accelerator on windows, it takes at least
200ms to initialize one cpu.  For a 4-core VM, it takes:

        before          800ms -- 1000ms
        after           200ms

Information about the processor on the host:

        Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz

See another email(to Eduardo) for more information.

Thanks,
Zhenyu