Re: [RFC v6 12/13] intel_iommu: Do not notify regular iotlb to device-iotlb notifiers

["罗勇刚(Yonggang Luo)" <luoyonggang@gmail.com>]

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On Wed, Aug 26, 2020 at 10:42 PM Eugenio Pérez <eperezma@redhat.com> wrote:

> This improves performance in case of netperf with vhost-net:
> * TCP_STREAM: From 9049.59Mbit/s to 9049.59Mbit/s (13%)
>
What's improvement ? they are the same


> * TCP_RR: From 8464.73 trans/s to 8932.703333 trans/s (5.5%)
> * UDP_RR: From 8562.08 trans/s to 9005.62/s (5.1%)
> * UDP_STREAM: No change observed (insignificant 0.1% improvement)
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>  hw/i386/intel_iommu.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index ddb828da1f..7620a1abbf 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -1960,6 +1960,12 @@ static void
> vtd_iotlb_domain_invalidate(IntelIOMMUState *s, uint16_t domain_id)
>      vtd_iommu_unlock(s);
>
>      QLIST_FOREACH(vtd_as, &s->vtd_as_with_notifiers, next) {
> +        if (vtd_as->iommu.iommu_notify_flags & IOMMU_NOTIFIER_DEVIOTLB) {
> +            /* If IOMMU memory region is DEVICE IOTLB type, it does not
> make
> +             * sense to send regular IOMMU notifications. */
> +            continue;
> +        }
> +
>          if (!vtd_dev_to_context_entry(s, pci_bus_num(vtd_as->bus),
>                                        vtd_as->devfn, &ce) &&
>              domain_id == vtd_get_domain_id(s, &ce)) {
> --
> 2.18.1
>
>
>

-- 
         此致
礼
罗勇刚
Yours
    sincerely,
Yonggang Luo

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