Re: Fwd: Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
Hi Stephen, Benjamin forwarded me your email stating: I have been playing with userspace-rcu which has a number of neat lockless routines for queuing and hashing. But there aren't kernel versions and several of them may require cmpxchg to work. Just FYI, I made sure a few years ago that cmpxchg is implemented on all architectures within the Linux kernel (using a interrupt disable fallback on the cases where it is not supported architecturally, on UP-only architectures), so we should be good to use the lock-free structures as-is in the kernel on this front. As for the RCU use by these structures, userspace RCU has very much the same semantic as in the kernel, so we can implement and test these structures in userspace and eventually port them to the kernel as needed. Lai Jiangshan is actively working at making sure the user-level implementation of the RCU lock-free hash table (currently in a development branch of the userspace RCU git tree : urcu/ht-shrink, not yet in master) is suitable for use in the Linux kernel too. Best regards, Mathieu -- Mathieu Desnoyers Operating System Efficiency RD Consultant EfficiOS Inc. http://www.efficios.com ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
I have been playing with userspace-rcu which has a number of neat lockless routines for queuing and hashing. But there aren't kernel versions and several of them may require cmpxchg to work. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Wed, 16 Nov 2011 09:23:17 +0200, Michael S. Tsirkin m...@redhat.com wrote: On Wed, Nov 16, 2011 at 10:34:42AM +1030, Rusty Russell wrote: On Mon, 14 Nov 2011 15:05:07 +0200, Michael S. Tsirkin m...@redhat.com wrote: On Mon, Nov 14, 2011 at 02:25:17PM +0200, Pekka Enberg wrote: On Mon, Nov 14, 2011 at 4:04 AM, Asias He asias.he...@gmail.com wrote: Why both the bandwidth and latency performance are dropping so dramatically with multiple VQ? What's the expected benefit from multiple VQs Heh, the original patchset didn't mention this :) It really should. They are supposed to speed up networking for high smp guests. If we have one queue per guest CPU, does this allow us to run lockless? Thanks, Rusty. LLTX? It's supposed to be deprecated, isn't it? I was referring back to Subject: virtio net lockless ring which Stephen sent back in June, nothing more specific. I assumed from his query that this was still an active area of exploration... Stephen? Thanks, Rusty. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
jason wang jasow...@redhat.com wrote on 11/16/2011 11:40:45 AM: Hi Jason, Have any thought in mind to solve the issue of flow handling? So far nothing concrete. Maybe some performance numbers first is better, it would let us know where we are. During the test of my patchset, I find big regression of small packet transmission, and more retransmissions were noticed. This maybe also the issue of flow affinity. One interesting things is to see whether this happens in your patches :) I haven't got any results for small packet, but will run this week and send an update. I remember my earlier patches having regression for small packets. I've played with a basic flow director implementation based on my series which want to make sure the packets of a flow was handled by the same vhost thread/guest vcpu. This is done by: - bind virtqueue to guest cpu - record the hash to queue mapping when guest sending packets and use this mapping to choose the virtqueue when forwarding packets to guest Test shows some help during for receiving packets from external host and packet sending to local host. But it would hurt the performance of sending packets to remote host. This is not the perfect solution as it can not handle guest moving processes among vcpus, I plan to try accelerate RFS and sharing the mapping between host and guest. Anyway this is just for receiving, the small packet sending need more thoughts. I don't recollect small packet performance for guest-local host. Also, using multiple tuns devices on the bridge (instead of mq-tun) balances the rx/tx of a flow to a single vq. Then you can avoid mq-tun with it's queue selector function, etc. Have you tried it? I will run my tests this week and get back. thanks, - KK ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On 11/16/2011 05:09 PM, Krishna Kumar2 wrote: jason wang jasow...@redhat.com wrote on 11/16/2011 11:40:45 AM: Hi Jason, Have any thought in mind to solve the issue of flow handling? So far nothing concrete. Maybe some performance numbers first is better, it would let us know where we are. During the test of my patchset, I find big regression of small packet transmission, and more retransmissions were noticed. This maybe also the issue of flow affinity. One interesting things is to see whether this happens in your patches :) I haven't got any results for small packet, but will run this week and send an update. I remember my earlier patches having regression for small packets. I've played with a basic flow director implementation based on my series which want to make sure the packets of a flow was handled by the same vhost thread/guest vcpu. This is done by: - bind virtqueue to guest cpu - record the hash to queue mapping when guest sending packets and use this mapping to choose the virtqueue when forwarding packets to guest Test shows some help during for receiving packets from external host and packet sending to local host. But it would hurt the performance of sending packets to remote host. This is not the perfect solution as it can not handle guest moving processes among vcpus, I plan to try accelerate RFS and sharing the mapping between host and guest. Anyway this is just for receiving, the small packet sending need more thoughts. I don't recollect small packet performance for guest-local host. Also, using multiple tuns devices on the bridge (instead of mq-tun) balances the rx/tx of a flow to a single vq. Then you can avoid mq-tun with it's queue selector function, etc. Have you tried it? I remember it works when I test your patchset early this year, but don't measure its performance. If multiple tuns devices were used, the mac address table would be updated very frequently and packets can not be forwarded in parallel ( unless we make bridge to support multiqueue ). I will run my tests this week and get back. thanks, - KK ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Tue, 2011-11-15 at 10:14 +0530, Krishna Kumar2 wrote: Sasha Levin levinsasha...@gmail.com wrote on 11/14/2011 03:45:40 PM: Why both the bandwidth and latency performance are dropping so dramatically with multiple VQ? It looks like theres no hash sync between host and guest, which makes the RX VQ change for every packet. This is my guess. Yes, I confirmed this happens for macvtap. I am using ixgbe - it calls skb_record_rx_queue when a skb is allocated, but sets rxhash when a packet arrives. Macvtap is relying on record_rx_queue first ahead of rxhash (as part of my patch making macvtap multiqueue), hence different skbs result in macvtap selecting different vq's. I'm seeing this behavior in non-macvtep related setup as well (simple tap - virtio-net). -- Sasha. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On 11/15/2011 12:44 PM, Krishna Kumar2 wrote:
Sasha Levin levinsasha...@gmail.com wrote on 11/14/2011 03:45:40 PM:
Why both the bandwidth and latency performance are dropping so
dramatically with multiple VQ?
It looks like theres no hash sync between host and guest, which makes
the RX VQ change for every packet. This is my guess.
Yes, I confirmed this happens for macvtap. I am
using ixgbe - it calls skb_record_rx_queue when
a skb is allocated, but sets rxhash when a packet
arrives. Macvtap is relying on record_rx_queue
first ahead of rxhash (as part of my patch making
macvtap multiqueue), hence different skbs result
in macvtap selecting different vq's.
Reordering macvtap to use rxhash first results in
all packets going to the same VQ. The code snippet
is:
{
...
if (!numvtaps)
goto out;
rxq = skb_get_rxhash(skb);
if (rxq) {
tap = rcu_dereference(vlan-taps[rxq % numvtaps]);
if (tap)
goto out;
}
if (likely(skb_rx_queue_recorded(skb))) {
rxq = skb_get_rx_queue(skb);
while (unlikely(rxq = numvtaps))
rxq -= numvtaps;
tap = rcu_dereference(vlan-taps[rxq]);
if (tap)
goto out;
}
}
I will submit a patch for macvtap separately. I am working
towards the other issue pointed out - different vhost
threads handling rx/tx of a single flow.
Hello Krishna:
Have any thought in mind to solve the issue of flow handling?
Maybe some performance numbers first is better, it would let us know
where we are. During the test of my patchset, I find big regression of
small packet transmission, and more retransmissions were noticed. This
maybe also the issue of flow affinity. One interesting things is to see
whether this happens in your patches :)
I've played with a basic flow director implementation based on my series
which want to make sure the packets of a flow was handled by the same
vhost thread/guest vcpu. This is done by:
- bind virtqueue to guest cpu
- record the hash to queue mapping when guest sending packets and use
this mapping to choose the virtqueue when forwarding packets to guest
Test shows some help during for receiving packets from external host and
packet sending to local host. But it would hurt the performance of
sending packets to remote host. This is not the perfect solution as it
can not handle guest moving processes among vcpus, I plan to try
accelerate RFS and sharing the mapping between host and guest.
Anyway this is just for receiving, the small packet sending need more
thoughts.
Thanks
thanks,
- KK
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Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Wed, Nov 16, 2011 at 10:34:42AM +1030, Rusty Russell wrote: On Mon, 14 Nov 2011 15:05:07 +0200, Michael S. Tsirkin m...@redhat.com wrote: On Mon, Nov 14, 2011 at 02:25:17PM +0200, Pekka Enberg wrote: On Mon, Nov 14, 2011 at 4:04 AM, Asias He asias.he...@gmail.com wrote: Why both the bandwidth and latency performance are dropping so dramatically with multiple VQ? What's the expected benefit from multiple VQs Heh, the original patchset didn't mention this :) It really should. They are supposed to speed up networking for high smp guests. If we have one queue per guest CPU, does this allow us to run lockless? Thanks, Rusty. LLTX? It's supposed to be deprecated, isn't it? -- MST ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Mon, 2011-11-14 at 10:04 +0800, Asias He wrote: Hi, Shsha On 11/13/2011 11:00 PM, Sasha Levin wrote: On Sun, 2011-11-13 at 12:24 +0200, Michael S. Tsirkin wrote: On Sat, Nov 12, 2011 at 12:12:01AM +0200, Sasha Levin wrote: This is a patch based on Krishna Kumar's patch series which implements multiple VQ support for virtio-net. The patch was tested with ver3 of the patch. Cc: Krishna Kumarkrkum...@in.ibm.com Cc: Michael S. Tsirkinm...@redhat.com Cc: Rusty Russellru...@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: net...@vger.kernel.org Signed-off-by: Sasha Levinlevinsasha...@gmail.com Any performance numbers? I tried finding a box with more than two cores so I could test it on something like that as well. From what I see this patch causes a performance regression on my 2 core box. I'll send an updated KVM tools patch in a bit as well. Before: # netperf -H 192.168.33.4,ipv4 -t TCP_RR MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 16384 87380 11 10.0011160.63 16384 87380 # netperf -H 192.168.33.4,ipv4 -t UDP_RR MIGRATED UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 122880 122880 11 10.0012072.64 229376 229376 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 16384 1638410.004654.50 netperf -H 192.168.33.4,ipv4 -t TCP_STREAM -- -m 128 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 1638412810.00 635.45 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Socket Message Elapsed Messages SizeSize Time Okay Errors Throughput bytes bytessecs# # 10^6bits/sec 122880 65507 10.00 113894 05968.54 229376 10.00 89373 4683.54 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM -- -m 128 MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Socket Message Elapsed Messages SizeSize Time Okay Errors Throughput bytes bytessecs# # 10^6bits/sec 122880 128 10.00 550634 0 56.38 229376 10.00 398786 40.84 After: # netperf -H 192.168.33.4,ipv4 -t TCP_RR MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 16384 87380 11 10.008952.47 16384 87380 # netperf -H 192.168.33.4,ipv4 -t UDP_RR MIGRATED UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 122880 122880 11 10.009534.52 229376 229376 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 16384 1638410.132278.23 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM -- -m 128 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 1638412810.00 623.27 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM MIGRATED UDP STREAM TEST
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Mon, Nov 14, 2011 at 02:25:17PM +0200, Pekka Enberg wrote: On Mon, Nov 14, 2011 at 4:04 AM, Asias He asias.he...@gmail.com wrote: Why both the bandwidth and latency performance are dropping so dramatically with multiple VQ? What's the expected benefit from multiple VQs Heh, the original patchset didn't mention this :) It really should. They are supposed to speed up networking for high smp guests. i.e. why are doing the patches Sasha? -- MST ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
Hi, Shsha On 11/13/2011 11:00 PM, Sasha Levin wrote: On Sun, 2011-11-13 at 12:24 +0200, Michael S. Tsirkin wrote: On Sat, Nov 12, 2011 at 12:12:01AM +0200, Sasha Levin wrote: This is a patch based on Krishna Kumar's patch series which implements multiple VQ support for virtio-net. The patch was tested with ver3 of the patch. Cc: Krishna Kumarkrkum...@in.ibm.com Cc: Michael S. Tsirkinm...@redhat.com Cc: Rusty Russellru...@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: net...@vger.kernel.org Signed-off-by: Sasha Levinlevinsasha...@gmail.com Any performance numbers? I tried finding a box with more than two cores so I could test it on something like that as well. From what I see this patch causes a performance regression on my 2 core box. I'll send an updated KVM tools patch in a bit as well. Before: # netperf -H 192.168.33.4,ipv4 -t TCP_RR MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 16384 87380 11 10.0011160.63 16384 87380 # netperf -H 192.168.33.4,ipv4 -t UDP_RR MIGRATED UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 122880 122880 11 10.0012072.64 229376 229376 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 16384 1638410.004654.50 netperf -H 192.168.33.4,ipv4 -t TCP_STREAM -- -m 128 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 1638412810.00 635.45 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Socket Message Elapsed Messages SizeSize Time Okay Errors Throughput bytes bytessecs# # 10^6bits/sec 122880 65507 10.00 113894 05968.54 229376 10.00 89373 4683.54 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM -- -m 128 MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Socket Message Elapsed Messages SizeSize Time Okay Errors Throughput bytes bytessecs# # 10^6bits/sec 122880 128 10.00 550634 0 56.38 229376 10.00 398786 40.84 After: # netperf -H 192.168.33.4,ipv4 -t TCP_RR MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 16384 87380 11 10.008952.47 16384 87380 # netperf -H 192.168.33.4,ipv4 -t UDP_RR MIGRATED UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 122880 122880 11 10.009534.52 229376 229376 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 16384 1638410.132278.23 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM -- -m 128 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 1638412810.00 623.27 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Socket Message Elapsed Messages SizeSize Time Okay Errors Throughput bytes bytessecs# # 10^6bits/sec 122880 65507 10.00 136930 0
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Mon, Nov 14, 2011 at 4:04 AM, Asias He asias.he...@gmail.com wrote: Why both the bandwidth and latency performance are dropping so dramatically with multiple VQ? What's the expected benefit from multiple VQs i.e. why are doing the patches Sasha? ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
Sasha Levin levinsasha...@gmail.com wrote on 11/14/2011 03:45:40 PM:
Why both the bandwidth and latency performance are dropping so
dramatically with multiple VQ?
It looks like theres no hash sync between host and guest, which makes
the RX VQ change for every packet. This is my guess.
Yes, I confirmed this happens for macvtap. I am
using ixgbe - it calls skb_record_rx_queue when
a skb is allocated, but sets rxhash when a packet
arrives. Macvtap is relying on record_rx_queue
first ahead of rxhash (as part of my patch making
macvtap multiqueue), hence different skbs result
in macvtap selecting different vq's.
Reordering macvtap to use rxhash first results in
all packets going to the same VQ. The code snippet
is:
{
...
if (!numvtaps)
goto out;
rxq = skb_get_rxhash(skb);
if (rxq) {
tap = rcu_dereference(vlan-taps[rxq % numvtaps]);
if (tap)
goto out;
}
if (likely(skb_rx_queue_recorded(skb))) {
rxq = skb_get_rx_queue(skb);
while (unlikely(rxq = numvtaps))
rxq -= numvtaps;
tap = rcu_dereference(vlan-taps[rxq]);
if (tap)
goto out;
}
}
I will submit a patch for macvtap separately. I am working
towards the other issue pointed out - different vhost
threads handling rx/tx of a single flow.
thanks,
- KK
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Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Sat, Nov 12, 2011 at 12:12:01AM +0200, Sasha Levin wrote:
This is a patch based on Krishna Kumar's patch series which implements
multiple VQ support for virtio-net.
The patch was tested with ver3 of the patch.
Cc: Krishna Kumar krkum...@in.ibm.com
Cc: Michael S. Tsirkin m...@redhat.com
Cc: Rusty Russell ru...@rustcorp.com.au
Cc: virtualization@lists.linux-foundation.org
Cc: net...@vger.kernel.org
Signed-off-by: Sasha Levin levinsasha...@gmail.com
Any performance numbers?
---
tools/kvm/include/kvm/virtio-pci.h |2 +-
tools/kvm/virtio/net.c | 94 +++
2 files changed, 52 insertions(+), 44 deletions(-)
diff --git a/tools/kvm/include/kvm/virtio-pci.h
b/tools/kvm/include/kvm/virtio-pci.h
index 2bbb271..94d20ee 100644
--- a/tools/kvm/include/kvm/virtio-pci.h
+++ b/tools/kvm/include/kvm/virtio-pci.h
@@ -6,7 +6,7 @@
#include linux/types.h
-#define VIRTIO_PCI_MAX_VQ3
+#define VIRTIO_PCI_MAX_VQ16
#define VIRTIO_PCI_MAX_CONFIG1
struct kvm;
diff --git a/tools/kvm/virtio/net.c b/tools/kvm/virtio/net.c
index cee2b5b..0754795 100644
--- a/tools/kvm/virtio/net.c
+++ b/tools/kvm/virtio/net.c
@@ -27,9 +27,8 @@
#include sys/wait.h
#define VIRTIO_NET_QUEUE_SIZE128
-#define VIRTIO_NET_NUM_QUEUES2
-#define VIRTIO_NET_RX_QUEUE 0
-#define VIRTIO_NET_TX_QUEUE 1
+#define VIRTIO_NET_NUM_QUEUES16
+#define VIRTIO_NET_IS_RX_QUEUE(x)(((x) % 2) == 0)
struct net_dev;
@@ -49,14 +48,13 @@ struct net_dev {
struct virtio_net_configconfig;
u32 features;
- pthread_t io_rx_thread;
- pthread_mutex_t io_rx_lock;
- pthread_cond_t io_rx_cond;
-
- pthread_t io_tx_thread;
- pthread_mutex_t io_tx_lock;
- pthread_cond_t io_tx_cond;
+ pthread_t io_thread[VIRTIO_NET_NUM_QUEUES];
+ pthread_mutex_t io_lock[VIRTIO_NET_NUM_QUEUES];
+ pthread_cond_t io_cond[VIRTIO_NET_NUM_QUEUES];
+ int rx_vq_num;
+ int tx_vq_num;
+ int vq_num;
int tap_fd;
chartap_name[IFNAMSIZ];
@@ -78,17 +76,22 @@ static void *virtio_net_rx_thread(void *p)
struct net_dev *ndev = p;
u16 out, in;
u16 head;
- int len;
+ int len, queue_num;
+
+ mutex_lock(ndev-mutex);
+ queue_num = ndev-rx_vq_num * 2;
+ ndev-tx_vq_num++;
+ mutex_unlock(ndev-mutex);
kvm = ndev-kvm;
- vq = ndev-vqs[VIRTIO_NET_RX_QUEUE];
+ vq = ndev-vqs[queue_num];
while (1) {
- mutex_lock(ndev-io_rx_lock);
+ mutex_lock(ndev-io_lock[queue_num]);
if (!virt_queue__available(vq))
- pthread_cond_wait(ndev-io_rx_cond, ndev-io_rx_lock);
- mutex_unlock(ndev-io_rx_lock);
+ pthread_cond_wait(ndev-io_cond[queue_num],
ndev-io_lock[queue_num]);
+ mutex_unlock(ndev-io_lock[queue_num]);
while (virt_queue__available(vq)) {
@@ -99,7 +102,7 @@ static void *virtio_net_rx_thread(void *p)
virt_queue__set_used_elem(vq, head, len);
/* We should interrupt guest right now, otherwise
latency is huge. */
- ndev-vtrans.trans_ops-signal_vq(kvm, ndev-vtrans,
VIRTIO_NET_RX_QUEUE);
+ ndev-vtrans.trans_ops-signal_vq(kvm, ndev-vtrans,
queue_num);
}
}
@@ -117,16 +120,21 @@ static void *virtio_net_tx_thread(void *p)
struct net_dev *ndev = p;
u16 out, in;
u16 head;
- int len;
+ int len, queue_num;
+
+ mutex_lock(ndev-mutex);
+ queue_num = ndev-tx_vq_num * 2 + 1;
+ ndev-tx_vq_num++;
+ mutex_unlock(ndev-mutex);
kvm = ndev-kvm;
- vq = ndev-vqs[VIRTIO_NET_TX_QUEUE];
+ vq = ndev-vqs[queue_num];
while (1) {
- mutex_lock(ndev-io_tx_lock);
+ mutex_lock(ndev-io_lock[queue_num]);
if (!virt_queue__available(vq))
- pthread_cond_wait(ndev-io_tx_cond, ndev-io_tx_lock);
- mutex_unlock(ndev-io_tx_lock);
+ pthread_cond_wait(ndev-io_cond[queue_num],
ndev-io_lock[queue_num]);
+ mutex_unlock(ndev-io_lock[queue_num]);
while (virt_queue__available(vq)) {
@@ -137,7 +145,7 @@ static void *virtio_net_tx_thread(void *p)
virt_queue__set_used_elem(vq, head, len);
}
- ndev-vtrans.trans_ops-signal_vq(kvm, ndev-vtrans,
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Sun, 2011-11-13 at 12:24 +0200, Michael S. Tsirkin wrote: On Sat, Nov 12, 2011 at 12:12:01AM +0200, Sasha Levin wrote: This is a patch based on Krishna Kumar's patch series which implements multiple VQ support for virtio-net. The patch was tested with ver3 of the patch. Cc: Krishna Kumar krkum...@in.ibm.com Cc: Michael S. Tsirkin m...@redhat.com Cc: Rusty Russell ru...@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: net...@vger.kernel.org Signed-off-by: Sasha Levin levinsasha...@gmail.com Any performance numbers? I tried finding a box with more than two cores so I could test it on something like that as well. From what I see this patch causes a performance regression on my 2 core box. I'll send an updated KVM tools patch in a bit as well. Before: # netperf -H 192.168.33.4,ipv4 -t TCP_RR MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 16384 87380 11 10.0011160.63 16384 87380 # netperf -H 192.168.33.4,ipv4 -t UDP_RR MIGRATED UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 122880 122880 11 10.0012072.64 229376 229376 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 16384 1638410.004654.50 netperf -H 192.168.33.4,ipv4 -t TCP_STREAM -- -m 128 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 1638412810.00 635.45 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Socket Message Elapsed Messages SizeSize Time Okay Errors Throughput bytes bytessecs# # 10^6bits/sec 122880 65507 10.00 113894 05968.54 229376 10.00 89373 4683.54 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM -- -m 128 MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Socket Message Elapsed Messages SizeSize Time Okay Errors Throughput bytes bytessecs# # 10^6bits/sec 122880 128 10.00 550634 0 56.38 229376 10.00 398786 40.84 After: # netperf -H 192.168.33.4,ipv4 -t TCP_RR MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 16384 87380 11 10.008952.47 16384 87380 # netperf -H 192.168.33.4,ipv4 -t UDP_RR MIGRATED UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET : first burst 0 Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size SizeTime Rate bytes Bytes bytesbytes secs.per sec 122880 122880 11 10.009534.52 229376 229376 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 16384 1638410.132278.23 # netperf -H 192.168.33.4,ipv4 -t TCP_STREAM -- -m 128 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.4 (192.168.33.4) port 0 AF_INET Recv SendSend Socket Socket Message Elapsed Size SizeSize Time Throughput bytes bytes bytessecs.10^6bits/sec 87380 1638412810.00 623.27 # netperf -H 192.168.33.4,ipv4 -t UDP_STREAM MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
Re: [RFC] kvm tools: Implement multiple VQ for virtio-net
On Sun, 2011-11-13 at 17:00 +0200, Sasha Levin wrote: On Sun, 2011-11-13 at 12:24 +0200, Michael S. Tsirkin wrote: On Sat, Nov 12, 2011 at 12:12:01AM +0200, Sasha Levin wrote: This is a patch based on Krishna Kumar's patch series which implements multiple VQ support for virtio-net. The patch was tested with ver3 of the patch. Cc: Krishna Kumar krkum...@in.ibm.com Cc: Michael S. Tsirkin m...@redhat.com Cc: Rusty Russell ru...@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: net...@vger.kernel.org Signed-off-by: Sasha Levin levinsasha...@gmail.com Any performance numbers? I tried finding a box with more than two cores so I could test it on something like that as well. From what I see this patch causes a performance regression on my 2 core box. [snip] After discussing it with Michael, we found out that for a single TCP flow the guest signals the same TX VQ, but the RX VQ keeps changing - which means that theres missing host-guest synchronization of hash flow. -- Sasha. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
