From: Paolo Bonzini <pbonzini@redhat.com>
To: "Jan Kiszka" <jan.kiszka@web.de>, "Peter Xu" <peterx@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Cc: qemu-devel@nongnu.org, imammedo@redhat.com, rth@twiddle.net,
ehabkost@redhat.com, jasowang@redhat.com, marcel@redhat.com,
mst@redhat.com, alex.williamson@redhat.com, wexu@redhat.com
Subject: Re: [Qemu-devel] [PATCH v5 00/18] IOMMU: Enable interrupt remapping for Intel IOMMU
Date: Mon, 9 May 2016 13:50:26 +0200 [thread overview]
Message-ID: <57307982.5070309@redhat.com> (raw)
In-Reply-To: <57282B44.8080407@web.de>
On 03/05/2016 06:38, Jan Kiszka wrote:
> Yes, this doesn't look good from the performance POV. Given that most
> EOIs of the APICs will not trigger a message to an IOAPIC and userspace
> exits are expensive, that should be measurable.
>
> But you should optimize route updating a bit: I noticed real delays
> (almost a second) when reprogramming all IOAPIC pins during Jailhouse
> handover. That's because of the heavyweight synchronize_srcu we have on
> each route change. Even if that is an extreme case, you should try to
> reduce route updates to only those that were actually affected by an
> IRTE change.
It's okay to make it synchronize_srcu_expedited. Unlike RCU, expediting
SRCU grace periods doesn't have an impact on the whole system (the
reason why KVM uses SRCU here is exactly to avoid
synchronize_rcu_expedited).
Of course, optimizing userspace cannot hurt either.
Paolo
next prev parent reply other threads:[~2016-05-09 11:50 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-28 7:05 [Qemu-devel] [PATCH v5 00/18] IOMMU: Enable interrupt remapping for Intel IOMMU Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 01/18] acpi: enable INTR for DMAR report structure Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 02/18] intel_iommu: allow queued invalidation for IR Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 03/18] intel_iommu: set IR bit for ECAP register Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 04/18] acpi: add DMAR scope definition for root IOAPIC Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 05/18] intel_iommu: define interrupt remap table addr register Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 06/18] intel_iommu: handle interrupt remap enable Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 07/18] intel_iommu: define several structs for IOMMU IR Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 08/18] intel_iommu: provide helper function vtd_get_iommu Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 09/18] intel_iommu: add IR translation faults defines Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 10/18] intel_iommu: Add support for PCI MSI remap Peter Xu
2016-04-28 7:32 ` Jan Kiszka
2016-04-28 8:06 ` Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 11/18] q35: ioapic: add support for emulated IOAPIC IR Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 12/18] ioapic: introduce ioapic_entry_parse() helper Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 13/18] intel_iommu: add support for split irqchip Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 14/18] q35: add "intremap" parameter to enable IR Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 15/18] intel_iommu: introduce IEC notifiers Peter Xu
2016-04-28 7:26 ` Jan Kiszka
2016-04-28 8:29 ` Peter Xu
2016-04-28 8:36 ` Jan Kiszka
2016-04-28 8:49 ` Peter Xu
2016-04-28 15:56 ` David Kiarie
2016-04-29 2:43 ` Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 16/18] ioapic: register VT-d IEC invalidate notifier Peter Xu
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 17/18] ioapic: keep RO bits for IOAPIC entry Peter Xu
2016-04-29 19:42 ` Radim Krčmář
2016-04-28 7:05 ` [Qemu-devel] [PATCH v5 18/18] ioapic: clear remote irr bit for edge-triggered interrupts Peter Xu
2016-04-29 19:46 ` Radim Krčmář
2016-04-28 7:12 ` [Qemu-devel] [PATCH v5 00/18] IOMMU: Enable interrupt remapping for Intel IOMMU Peter Xu
2016-04-28 7:19 ` Jan Kiszka
2016-04-28 9:18 ` Peter Xu
2016-04-28 9:32 ` Jan Kiszka
2016-04-29 19:52 ` Radim Krčmář
2016-05-03 3:22 ` Peter Xu
2016-05-03 4:38 ` Jan Kiszka
2016-05-03 5:30 ` Peter Xu
2016-05-03 5:40 ` Jan Kiszka
2016-05-03 6:00 ` Peter Xu
2016-05-03 6:09 ` Jan Kiszka
2016-05-09 11:50 ` Paolo Bonzini [this message]
2016-04-28 9:30 ` [Qemu-devel] [PATCH 19/18] intel_iommu: Add support for Extended Interrupt Mode Jan Kiszka
2016-04-29 2:54 ` Peter Xu
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