From: David Woodhouse <dwmw2@infradead.org>
To: Tom Lendacky <thomas.lendacky@amd.com>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"H . Peter Anvin" <hpa@zytor.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"Paul E . McKenney" <paulmck@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"rcu@vger.kernel.org" <rcu@vger.kernel.org>,
"mimoja@mimoja.de" <mimoja@mimoja.de>,
"hewenliang4@huawei.com" <hewenliang4@huawei.com>,
"hushiyuan@huawei.com" <hushiyuan@huawei.com>,
"luolongjun@huawei.com" <luolongjun@huawei.com>,
"hejingxian@huawei.com" <hejingxian@huawei.com>
Subject: Re: [PATCH v3 0/9] Parallel CPU bringup for x86_64
Date: Thu, 16 Dec 2021 19:59:57 +0000 [thread overview]
Message-ID: <E92CDF5A-229A-4D57-8C38-2E89373A37AD@infradead.org> (raw)
In-Reply-To: <0247ce40-1f1e-3581-95a2-8a1d51cb8fad@amd.com>
On 16 December 2021 19:55:36 GMT, Tom Lendacky <thomas.lendacky@amd.com> wrote:
>On 12/16/21 1:52 PM, David Woodhouse wrote:
>> On Thu, 2021-12-16 at 10:27 -0600, Tom Lendacky wrote:
>>> On 12/15/21 8:56 AM, David Woodhouse wrote:
>>>
>>>> Doing the INIT/SIPI/SIPI in parallel for all APs and *then* waiting for
>>>> them shaves about 80% off the AP bringup time on a 96-thread socket
>>>> Skylake box (EC2 c5.metal) — from about 500ms to 100ms.
>>>>
>>>> There are more wins to be had with further parallelisation, but this is
>>>> the simple part.
>>>
>>> I applied this series and began booting a regular non-SEV guest and hit a
>>> failure at 39 vCPUs. No panic or warning, just a reset and OVMF was
>>> executing again. I'll try to debug what's going, but not sure how quickly
>>> I'll arrive at anything.
>>
>> I've pushed the SEV-ES fix to
>> https://git.infradead.org/users/dwmw2/linux.git/shortlog/refs/heads/parallel-5.16
>> and in doing so I've moved the 'no_parallel_bringup' command line
>> argument earlier in the series, to Thomas's "Support parallel startup
>> of secondary CPUs" commit (now 191f0899757). It would be interesting to
>> see if you can reproduce with just that much, both with and with
>> no_parallel_bringup. And then whether the subsequent commit that
>> actually enables the parallel INIT/SIPI/SIPI actually makes the
>> difference?
>>
>
>I'll pull it down and give it try.
Thanks. Note: don't use the whole thing; that last "parallel part2" patch in particular isn't ready. And probably isn't where the next low-hanging fruit is anyway.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
next prev parent reply other threads:[~2021-12-16 20:00 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-15 14:56 [PATCH v3 0/9] Parallel CPU bringup for x86_64 David Woodhouse
2021-12-15 14:56 ` [PATCH v3 1/9] x86/apic/x2apic: Fix parallel handling of cluster_mask David Woodhouse
2021-12-15 14:56 ` [PATCH v3 2/9] cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> David Woodhouse
2021-12-15 14:56 ` [PATCH v3 3/9] cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU David Woodhouse
2021-12-15 14:56 ` [PATCH v3 4/9] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() David Woodhouse
2021-12-15 14:56 ` [PATCH v3 5/9] x86/smpboot: Split up native_cpu_up into separate phases and document them David Woodhouse
2021-12-15 14:56 ` [PATCH v3 6/9] x86/smpboot: Support parallel startup of secondary CPUs David Woodhouse
2021-12-16 14:24 ` Tom Lendacky
2021-12-16 18:24 ` David Woodhouse
2021-12-16 19:00 ` Tom Lendacky
2021-12-16 19:20 ` David Woodhouse
2022-01-29 12:04 ` David Woodhouse
2022-01-31 13:59 ` Borislav Petkov
2022-02-01 10:25 ` David Woodhouse
2022-02-01 10:56 ` Borislav Petkov
2022-02-01 12:39 ` David Woodhouse
2022-02-01 12:56 ` Borislav Petkov
2022-02-01 13:02 ` David Woodhouse
2021-12-15 14:56 ` [PATCH v3 7/9] x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel David Woodhouse
2021-12-15 14:56 ` [PATCH v3 8/9] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup David Woodhouse
2021-12-15 14:56 ` [PATCH v3 9/9] x86/smpboot: Serialize topology updates for secondary bringup David Woodhouse
2021-12-16 16:27 ` [PATCH v3 0/9] Parallel CPU bringup for x86_64 Tom Lendacky
2021-12-16 19:24 ` David Woodhouse
2021-12-16 22:52 ` Tom Lendacky
2021-12-17 0:13 ` David Woodhouse
2021-12-17 10:09 ` Igor Mammedov
2021-12-17 15:40 ` David Woodhouse
2021-12-20 17:10 ` David Woodhouse
2021-12-20 18:54 ` Tom Lendacky
2021-12-20 21:29 ` David Woodhouse
2021-12-20 21:47 ` Tom Lendacky
2021-12-21 22:25 ` Tom Lendacky
2021-12-21 22:33 ` David Woodhouse
2021-12-17 17:48 ` Tom Lendacky
2021-12-17 19:11 ` David Woodhouse
2021-12-17 19:26 ` David Woodhouse
2021-12-17 20:15 ` Tom Lendacky
2021-12-17 19:46 ` Tom Lendacky
2021-12-17 20:13 ` David Woodhouse
2021-12-17 20:55 ` Tom Lendacky
2021-12-17 22:48 ` David Woodhouse
2022-01-28 9:54 ` David Woodhouse
2022-01-28 21:40 ` Sean Christopherson
2022-01-28 21:48 ` David Woodhouse
2022-01-29 9:22 ` David Woodhouse
2021-12-16 19:52 ` David Woodhouse
2021-12-16 19:55 ` Tom Lendacky
2021-12-16 19:59 ` David Woodhouse [this message]
2021-12-27 16:57 ` Paul Menzel
2021-12-28 11:34 ` Paul Menzel
2021-12-28 14:18 ` David Woodhouse
2021-12-29 13:18 ` Paul Menzel
2021-12-29 13:54 ` David Woodhouse
2022-02-14 13:45 ` Paul Menzel
2022-04-21 10:00 ` Mimoja
2022-04-22 21:19 ` Tom Lendacky
2022-06-01 8:30 ` David Woodhouse
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