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

[Eugenio Perez Martin]

On Wed, Aug 26, 2020 at 6:52 PM 罗勇刚(Yonggang Luo) <luoyonggang@gmail.com> wrote:
>
>
>
> 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
>

Ouch, it was from 1923.6 Mbit/s to 2175.13 Mbit/s. Thanks for notify
it, will fix in next revision!

>>
>> * 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