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From: Oliver Upton <oupton@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	Ben Gardon <bgardon@google.com>, Peter Shier <pshier@google.com>,
	David Matlack <dmatlack@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 00/17] KVM: arm64: Parallelize stage 2 fault handling
Date: Sat, 16 Apr 2022 06:23:46 +0000	[thread overview]
Message-ID: <Ylpg8l0BDlNpDWjs@google.com> (raw)
In-Reply-To: <20220415215901.1737897-1-oupton@google.com>

On Fri, Apr 15, 2022 at 09:58:44PM +0000, Oliver Upton wrote:

[...]

> 
> Smoke tested with KVM selftests + kvm_page_table_test w/ 2M hugetlb to
> exercise the table pruning code. Haven't done anything beyond this,
> sending as an RFC now to get eyes on the code.

Ok, got around to testing this thing a bit harder. Keep in mind that
permission faults at PAGE_SIZE granularity already go on the read side
of the lock. I used the dirty_log_perf_test with 4G/vCPU and anonymous
THP all the way up to 48 vCPUs. Here is the data as it compares to
5.18-rc2.

Dirty log time (split 2M -> 4K):

+-------+----------+-------------------+
| vCPUs | 5.18-rc2 | 5.18-rc2 + series |
+-------+----------+-------------------+
|     1 | 0.83s    | 0.85s             |
|     2 | 0.95s    | 1.07s             |
|     4 | 2.65s    | 1.13s             |
|     8 | 4.88s    | 1.33s             |
|    16 | 9.71s    | 1.73s             |
|    32 | 20.43s   | 3.99s             |
|    48 | 29.15s   | 6.28s             |
+-------+----------+-------------------+

The scaling of prefaulting pass looks better too (same config):

+-------+----------+-------------------+
| vCPUs | 5.18-rc2 | 5.18-rc2 + series |
+-------+----------+-------------------+
|     1 | 0.42s    | 0.18s             |
|     2 | 0.55s    | 0.19s             |
|     4 | 0.79s    | 0.27s             |
|     8 | 1.29s    | 0.35s             |
|    16 | 2.03s    | 0.53s             |
|    32 | 4.03s    | 1.01s             |
|    48 | 6.10s    | 1.51s             |
+-------+----------+-------------------+

--
Thanks,
Oliver
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  parent reply	other threads:[~2022-04-16  6:23 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-15 21:58 [RFC PATCH 00/17] KVM: arm64: Parallelize stage 2 fault handling Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 01/17] KVM: arm64: Directly read owner id field in stage2_pte_is_counted() Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 02/17] KVM: arm64: Only read the pte once per visit Oliver Upton
2022-04-21 16:12   ` Ben Gardon
2022-04-15 21:58 ` [RFC PATCH 03/17] KVM: arm64: Return the next table from map callbacks Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 04/17] KVM: arm64: Protect page table traversal with RCU Oliver Upton
2022-04-19  2:55   ` Ricardo Koller
2022-04-19  3:01     ` Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 05/17] KVM: arm64: Take an argument to indicate parallel walk Oliver Upton
2022-04-16 11:30   ` Marc Zyngier
2022-04-16 16:03     ` Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 06/17] KVM: arm64: Implement break-before-make sequence for parallel walks Oliver Upton
2022-04-20 16:55   ` Quentin Perret
2022-04-20 17:06     ` Oliver Upton
2022-04-21 16:57   ` Ben Gardon
2022-04-21 18:52     ` Oliver Upton
2022-04-26 21:32       ` Ben Gardon
2022-04-25 15:13   ` Sean Christopherson
2022-04-25 16:53     ` Oliver Upton
2022-04-25 18:16       ` Sean Christopherson
2022-04-15 21:58 ` [RFC PATCH 07/17] KVM: arm64: Enlighten perm relax path about " Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 08/17] KVM: arm64: Spin off helper for initializing table pte Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 09/17] KVM: arm64: Tear down unlinked page tables in parallel walk Oliver Upton
2022-04-21 13:21   ` Quentin Perret
2022-04-21 16:40     ` Oliver Upton
2022-04-22 16:00       ` Quentin Perret
2022-04-22 20:41         ` Oliver Upton
2022-05-03 14:17           ` Quentin Perret
2022-05-04  6:03             ` Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 10/17] KVM: arm64: Assume a table pte is already owned in post-order traversal Oliver Upton
2022-04-21 16:11   ` Ben Gardon
2022-04-21 17:16     ` Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 11/17] KVM: arm64: Move MMU cache init/destroy into helpers Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 12/17] KVM: arm64: Stuff mmu page cache in sub struct Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 13/17] KVM: arm64: Setup cache for stage2 page headers Oliver Upton
2022-04-15 21:58 ` [RFC PATCH 14/17] KVM: arm64: Punt last page reference to rcu callback for parallel walk Oliver Upton
2022-04-19  2:59   ` Ricardo Koller
2022-04-19  3:09     ` Ricardo Koller
2022-04-20  0:53       ` Oliver Upton
2022-09-08  0:52         ` David Matlack
2022-04-21 16:28   ` Ben Gardon
2022-04-15 21:58 ` [RFC PATCH 15/17] KVM: arm64: Allow parallel calls to kvm_pgtable_stage2_map() Oliver Upton
2022-04-15 21:59 ` [RFC PATCH 16/17] KVM: arm64: Enable parallel stage 2 MMU faults Oliver Upton
2022-04-21 16:35   ` Ben Gardon
2022-04-21 16:46     ` Oliver Upton
2022-04-21 17:03       ` Ben Gardon
2022-04-15 21:59 ` [RFC PATCH 17/17] TESTONLY: KVM: arm64: Add super lazy accounting of stage 2 table pages Oliver Upton
2022-04-15 23:35 ` [RFC PATCH 00/17] KVM: arm64: Parallelize stage 2 fault handling David Matlack
2022-04-16  0:04   ` Oliver Upton
2022-04-21 16:43     ` David Matlack
2022-04-16  6:23 ` Oliver Upton [this message]
2022-04-19 17:57 ` Ben Gardon
2022-04-19 18:36   ` Oliver Upton
2022-04-21 16:30     ` Ben Gardon
2022-04-21 16:37       ` Paolo Bonzini

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