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Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c |
Date: |
Thu, 31 May 2012 13:03:35 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 |
Il 31/05/2012 12:40, Jan Kiszka ha scritto:
> On 2012-05-31 12:03, Paolo Bonzini wrote:
>> Il 31/05/2012 10:23, Jan Kiszka ha scritto:
>>>>> @@ -922,6 +923,7 @@ set_rdt(E1000State *s, int index, uint32_t val)
>>>>> {
>>>>> s->check_rxov = 0;
>>>>> s->mac_reg[index] = val & 0xffff;
>>>>> + qemu_notify_event();
>>> This still looks like the wrong tool: Packets that can't be delivered
>>> are queued.
>>
>> Packets that are read from the tap but can't be delivered are queued;
>> packets that are left on the tap need qemu_notify_event to be flushed.
>>
>>> So we need to flush the queue and clear the blocked delivery
>>> there. qemu_flush_queued_packets appears more appropriate for this.
>>
>> Right, and qemu_flush_queued_packets needs to call qemu_notify_event
>> which makes the call in virtio-net unnecessary.
>>
>> Paolo
>>
>> diff --git a/hw/e1000.c b/hw/e1000.c
>> index 4573f13..43d933a 100644
>> --- a/hw/e1000.c
>> +++ b/hw/e1000.c
>> @@ -295,6 +295,7 @@ set_rx_control(E1000State *s, int index, uint32_t val)
>> s->rxbuf_min_shift = ((val / E1000_RCTL_RDMTS_QUAT) & 3) + 1;
>> DBGOUT(RX, "RCTL: %d, mac_reg[RCTL] = 0x%x\n", s->mac_reg[RDT],
>> s->mac_reg[RCTL]);
>> + qemu_flush_queued_packets(&s->nic->nc);
>> }
>>
>> static void
>> @@ -926,6 +927,9 @@ set_rdt(E1000State *s, int index, uint32_t val)
>> {
>> s->check_rxov = 0;
>> s->mac_reg[index] = val & 0xffff;
>> + if (e1000_has_rxbufs(s, 1)) {
>> + qemu_flush_queued_packets(&s->nic->nc);
>> + }
>> }
>>
>> static void
>> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
>> index 3f190d4..0974945 100644
>> --- a/hw/virtio-net.c
>> +++ b/hw/virtio-net.c
>> @@ -447,10 +447,6 @@ static void virtio_net_handle_rx(VirtIODevice *vdev,
>> VirtQueue *vq)
>> VirtIONet *n = to_virtio_net(vdev);
>>
>> qemu_flush_queued_packets(&n->nic->nc);
>> -
>> - /* We now have RX buffers, signal to the IO thread to break out of the
>> - * select to re-poll the tap file descriptor */
>> - qemu_notify_event();
>> }
>>
>> static int virtio_net_can_receive(VLANClientState *nc)
>> diff --git a/net.c b/net.c
>> index 1922d8a..fa846ae 100644
>> --- a/net.c
>> +++ b/net.c
>> @@ -491,7 +491,12 @@ void qemu_flush_queued_packets(VLANClientState *vc)
>> queue = vc->send_queue;
>> }
>>
>> - qemu_net_queue_flush(queue);
>> + if (qemu_net_queue_flush(queue)) {
>> + /* We emptied the queue successfully, signal to the IO thread to
>> repoll
>> + * the file descriptor (for tap, for example).
>> + */
>> + qemu_notify_event();
>> + }
>> }
>>
>> static ssize_t qemu_send_packet_async_with_flags(VLANClientState *sender,
>> diff --git a/net/queue.c b/net/queue.c
>> index 1ab5247..fd1c7e6 100644
>> --- a/net/queue.c
>> +++ b/net/queue.c
>> @@ -232,7 +232,7 @@ void qemu_net_queue_purge(NetQueue *queue,
>> VLANClientState *from)
>> }
>> }
>>
>> -void qemu_net_queue_flush(NetQueue *queue)
>> +bool qemu_net_queue_flush(NetQueue *queue)
>> {
>> while (!QTAILQ_EMPTY(&queue->packets)) {
>> NetPacket *packet;
>> @@ -248,7 +248,7 @@ void qemu_net_queue_flush(NetQueue *queue)
>> packet->size);
>> if (ret == 0) {
>> QTAILQ_INSERT_HEAD(&queue->packets, packet, entry);
>> - break;
>> + return 0;
>> }
>>
>> if (packet->sent_cb) {
>> @@ -257,4 +257,5 @@ void qemu_net_queue_flush(NetQueue *queue)
>>
>> g_free(packet);
>> }
>> + return 1;
>> }
>> diff --git a/net/queue.h b/net/queue.h
>> index a31958e..4bf6d3c 100644
>> --- a/net/queue.h
>> +++ b/net/queue.h
>> @@ -66,6 +66,6 @@ ssize_t qemu_net_queue_send_iov(NetQueue *queue,
>> NetPacketSent *sent_cb);
>>
>> void qemu_net_queue_purge(NetQueue *queue, VLANClientState *from);
>> -void qemu_net_queue_flush(NetQueue *queue);
>> +bool qemu_net_queue_flush(NetQueue *queue);
>>
>> #endif /* QEMU_NET_QUEUE_H */
>
> Looks good.
Luigi, please reply with a Tested-by when possible.
Paolo
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, (continued)
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Jan Kiszka, 2012/05/30
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Luigi Rizzo, 2012/05/30
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Paolo Bonzini, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Luigi Rizzo, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Jan Kiszka, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Jan Kiszka, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Luigi Rizzo, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Jan Kiszka, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Paolo Bonzini, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Jan Kiszka, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c,
Paolo Bonzini <=
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Stefan Weil, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Stefano Stabellini, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Paolo Bonzini, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Stefano Stabellini, 2012/05/31
- Re: [Qemu-devel] Proposed patch: huge RX speedup for hw/e1000.c, Paolo Bonzini, 2012/05/31