NetworkingTodo

Mst — Thu, 23 May 2013 10:43:24 GMT

Revision as of 10:43, 23 May 2013		Current revision
Line 2:		Line 2:
	currently most info is related to virtio-net.		currently most info is related to virtio-net.

-	Stabilization is highest priority currently.	+	TODO: add bugzilla entry links.
-	DOA test matrix (all combinations should work):	+
-	vhost: test both on and off, obviously	+
-	test: hotplug/unplug, vlan/mac filtering, netperf,	+
-	file copy both ways: scp, NFS, NTFS	+
-	guests: linux: release and debug kernels, windows	+
-	conditions: plain run, run while under migration,	+
-	vhost on/off migration	+
-	networking setup: simple, qos with cgroups	+
-	host configuration: host-guest, external-guest	+

-	=== vhost-net driver projects ===	+	=== projects in progress. contributions are still very wellcome!
-	* iovec length limitations	+
-	Developer: Jason Wang <jasowang@redhat.com>	+
-	Testing: guest to host file transfer on windows.	+

-	* mergeable buffers: fix host->guest BW regression	+	* vhost-net scalability tuning: threading for many VMs
-	Testing: netperf host to guest default flags	+	Plan: switch to workqueue shared by many VMs
-		+	www.mail-archive.com/kvm@vger.kernel.org/msg69868.html
-	* scalability tuning: threading for guest to guest	+	Developer: Shirley Ma?, MST
-	Developer: MST	+
	Testing: netperf guest to guest		Testing: netperf guest to guest

-	=== qemu projects ===	+	* multiqueue support in macvtap
-	* fix hotplug issues	+	multiqueue is only supported for tun.
-	Developer: MST	+	Add support for macvtap.
-	https://bugzilla.redhat.com/show_bug.cgi?id=623735	+	Developer: Jason Wang
-		+
-	* migration with multiple macs/vlans	+
-	Developer: Jason Wang	+
-	qemu only sends ping with the first mac/no vlan:	+
-	need to send it for all macs/vlan	+

-	* bugfix: crash with illegal fd= value on command line	+	* enable multiqueue by default
		+	Multiqueue causes regression in some workloads, thus
		+	it is off by default. Detect and enable/disable
		+	automatically so we can make it on by default
	Developer: Jason Wang		Developer: Jason Wang
-	Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=581750

-	=== virtio projects ===	+	* guest programmable mac/vlan filtering with macvtap
-	* suspend/resume support	+	Developer: Dragos Tatulea?, Amos Kong
		+	Status: [[GuestProgrammableMacVlanFiltering]]

-	* API extension: improve small packet/large buffer performance:	+	* bridge without promisc mode in NIC
		+	given hardware support, teach bridge
		+	to program mac/vlan filtering in NIC
		+	Helps performance and security on noisy LANs
		+	http://comments.gmane.org/gmane.linux.network/266546
		+	Developer: Vlad Yasevich
		+
		+	* reduce networking latency:
		+	allow handling short packets from softirq or VCPU context
		+	Plan:
		+	We are going through the scheduler 3 times
		+	(could be up to 5 if softirqd is involved)
		+	Consider RX: host irq -> io thread -> VCPU thread ->
		+	guest irq -> guest thread.
		+	This adds a lot of latency.
		+	We can cut it by some 1.5x if we do a bit of work
		+	either in the VCPU or softirq context.
		+	Testing: netperf TCP RR - should be improved drastically
		+	netperf TCP STREAM guest to host - no regression
		+	Developer: MST
		+
		+	* Flexible buffers: put virtio header inline with packet data
		+	https://patchwork.kernel.org/patch/1540471/
		+	Developer: MST
		+
		+	* device failover to allow migration with assigned devices
		+	https://fedoraproject.org/wiki/Features/Virt_Device_Failover
		+	Developer: Gal Hammer, Cole Robinson, Laine Stump, MST
		+
		+	* Reuse vringh code for better maintainability
		+	Developer: Rusty Russell
		+
		+	* Improve stats, make them more helpful for per analysis
		+	Developer: Sriram Narasimhan
		+
		+	=== projects that are not started yet - no owner ===
		+
		+	* netdev polling for virtio.
		+	See http://lkml.indiana.edu/hypermail/linux/kernel/1303.0/00553.html
		+
		+	* receive side zero copy
		+	The ideal is a NIC with accelerated RFS support,
		+	So we can feed the virtio rx buffers into the correct NIC queue.
		+	Depends on non promisc NIC support in bridge.
		+
		+	* IPoIB infiniband bridging
		+	Plan: implement macvtap for ipoib and virtio-ipoib
		+
		+	* RDMA bridging
		+
		+	* use kvm eventfd support for injecting level interrupts,
		+	enable vhost by default for level interrupts
		+
		+	* DMA emgine (IOAT) use in tun
		+
		+	* virtio API extension: improve small packet/large buffer performance:
	support "reposting" buffers for mergeable buffers,		support "reposting" buffers for mergeable buffers,
	support pool for indirect buffers		support pool for indirect buffers
		+
		+	=== vague ideas: path to implementation not clear
		+
	* ring redesign:		* ring redesign:
	find a way to test raw ring performance		find a way to test raw ring performance
	fix cacheline bounces		fix cacheline bounces
	reduce interrupts		reduce interrupts
-	Developer: MST
-	see patchset: virtio: put last seen used index into ring itself

-	=== projects involing other kernel components and/or networking stack ===
-	* guest programmable mac/vlan filtering with macvtap
-	Developer: Dragos Tatulea
-	Status: [[GuestProgrammableMacVlanFiltering]]

-	* bridge without promisc mode in NIC	+	* support more queues
-	given hardware support, teach bridge	+	We limit TUN to 8 queues
-	to program mac/vlan filtering in NIC	+
		+	* irq/numa affinity:
		+	networking goes much faster with irq pinning:
		+	both with and without numa.
		+	what can be done to make the non-pinned setup go faster?
		+
		+	* reduce conflict with VCPU thread
		+	if VCPU and networking run on same CPU,
		+	they conflict resulting in bad performance.
		+	Fix that, push vhost thread out to another CPU
		+	more aggressively.

	* rx mac filtering in tun		* rx mac filtering in tun
Line 68:		Line 115:
	* vlan filtering in tun		* vlan filtering in tun
	the need for this is still not understood as we have filtering in bridge		the need for this is still not understood as we have filtering in bridge
-	for small # if vlans we can use BPF

	* vlan filtering in bridge		* vlan filtering in bridge
	IGMP snooping in bridge should take vlans into account		IGMP snooping in bridge should take vlans into account

-	* zero copy tx/rx for macvtap
-	Developers: tx zero copy Shirley Ma; rx zero copy Xin Xiaohui
-
-	* multiqueue (involves all of vhost, qemu, virtio, networking stack)
-	Developer: Krishna Jumar
-	Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=632751
-
-	* kvm MSI interrupt injection fast path
-	Developer: MST
-
-	* kvm eventfd support for injecting level interrupts
-
-	* DMA emgine (IOAT) use in tun
-
-	* allow handling short packets from softirq context
-	Testing: netperf TCP STREAM guest to host
-	netperf TCP RR
-
-	* irq affinity:
-	networking goes much faster with irq pinning:
-	both with and without numa.
-	what can be done to make the non-pinned setup go faster?

	=== testing projects ===		=== testing projects ===
-	* Cover test matrix with autotest	+	Keeping networking stable is highest priority.
-	* Test with windows drivers, pass WHQL	+
		+	* Run weekly test on upstream HEAD covering test matrix with autotest

	=== non-virtio-net devices ===		=== non-virtio-net devices ===
	* e1000: stabilize		* e1000: stabilize
-	Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=602205

-	=== bugzilla entries for bugs fixed ===	+	=== test matrix ===
-	* verify these are ok upstream	+
-	https://bugzilla.redhat.com/show_bug.cgi?id=623552	+
-	https://bugzilla.redhat.com/show_bug.cgi?id=632747	+
-	https://bugzilla.redhat.com/show_bug.cgi?id=632745	+

-		+	DOA test matrix (all combinations should work):
-	=== abandoned projects: ===	+	vhost: test both on and off, obviously
-	* Add GSO/checksum offload support to AF_PACKET(raw) sockets.	+	test: hotplug/unplug, vlan/mac filtering, netperf,
-	status: incomplete	+	file copy both ways: scp, NFS, NTFS
-	* guest kernel 2.6.31 seems to work well. Under certain workloads,	+	guests: linux: release and debug kernels, windows
-	virtio performance has regressed with guest kernels 2.6.32 and up	+	conditions: plain run, run while under migration,
-	(but still better than userspace). A patch has been posted:	+	vhost on/off migration
-	http://www.spinics.net/lists/netdev/msg115292.html	+	networking setup: simple, qos with cgroups
-	status: might be fixed, need to test	+	host configuration: host-guest, external-guest

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