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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, "H . Peter Anvin" <hpa@zytor.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	rcu@vger.kernel.org, mimoja@mimoja.de, hewenliang4@huawei.com,
	hushiyuan@huawei.com, luolongjun@huawei.com,
	hejingxian@huawei.com
Subject: Re: [PATCH v3 0/9] Parallel CPU bringup for x86_64
Date: Thu, 16 Dec 2021 19:52:41 +0000	[thread overview]
Message-ID: <f0b4eddc2cdb3aae190bacd0a5285c393e4f8ea3.camel@infradead.org> (raw)
In-Reply-To: <761c1552-0ca0-403b-3461-8426198180d0@amd.com>

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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?

Thanks!

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  parent reply	other threads:[~2021-12-16 19:53 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 [this message]
2021-12-16 19:55     ` Tom Lendacky
2021-12-16 19:59       ` David Woodhouse
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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