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8836630f5d
Currently, the spapr-vlan device is trying to flush the RX queue after each RX buffer that has been added by the guest via the H_ADD_LOGICAL_LAN_BUFFER hypercall. In case the receive buffer pool was empty before, we only pass single packets to the guest this way. This can cause very bad performance if a sender is trying to stream fragmented UDP packets to the guest. For example when using the UDP_STREAM test from netperf with UDP packets that are much bigger than the MTU size, almost all UDP packets are dropped in the guest since the chances are quite high that at least one of the fragments got lost on the way. When flushing the receive queue, it's much better if we'd have a bunch of receive buffers available already, so that fragmented packets can be passed to the guest in one go. To do this, the spapr_vlan_receive() function should return 0 instead of -1 if there are no more receive buffers available, so that receive_disabled = 1 gets temporarily set for the receive queue, and we have to delay the queue flushing at the end of h_add_logical_lan_buffer() a little bit by using a timer, so that the guest gets a chance to add multiple RX buffers before we flush the queue again. This improves the UDP_STREAM test with the spapr-vlan device a lot: Running netserver -p 44444 -L <guestip> -f -D -4 in the guest, and netperf -p 44444 -L <hostip> -H <guestip> -t UDP_STREAM -l 60 -- -m 16384 in the host, I get the following values _without_ this patch: Socket Message Elapsed Messages Size Size Time Okay Errors Throughput bytes bytes secs # # 10^6bits/sec 229376 16384 60.00 1738970 0 3798.83 229376 60.00 23 0.05 That "0.05" means that almost all UDP packets got lost/discarded at the receiving side. With this patch applied, the value look much better: Socket Message Elapsed Messages Size Size Time Okay Errors Throughput bytes bytes secs # # 10^6bits/sec 229376 16384 60.00 1789104 0 3908.35 229376 60.00 22818 49.85 Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> |
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| .. | ||
| fsl_etsec | ||
| rocker | ||
| allwinner_emac.c | ||
| cadence_gem.c | ||
| dp8393x.c | ||
| e1000_regs.h | ||
| e1000.c | ||
| eepro100.c | ||
| etraxfs_eth.c | ||
| imx_fec.c | ||
| lan9118.c | ||
| lance.c | ||
| Makefile.objs | ||
| mcf_fec.c | ||
| milkymist-minimac2.c | ||
| mipsnet.c | ||
| ne2000-isa.c | ||
| ne2000.c | ||
| ne2000.h | ||
| opencores_eth.c | ||
| pcnet-pci.c | ||
| pcnet.c | ||
| pcnet.h | ||
| rtl8139.c | ||
| smc91c111.c | ||
| spapr_llan.c | ||
| stellaris_enet.c | ||
| vhost_net.c | ||
| virtio-net.c | ||
| vmware_utils.h | ||
| vmxnet3.c | ||
| vmxnet3.h | ||
| vmxnet_debug.h | ||
| vmxnet_rx_pkt.c | ||
| vmxnet_rx_pkt.h | ||
| vmxnet_tx_pkt.c | ||
| vmxnet_tx_pkt.h | ||
| xen_nic.c | ||
| xgmac.c | ||
| xilinx_axienet.c | ||
| xilinx_ethlite.c | ||