>ron minnich wrote: >> Let me ask what may seem to be a naive question to the linux world. I >> see you are doing a lot off solid work on adding block and network >> devices. The code for block and network devices >> is implemented in different ways. I've also seen this difference of >> inerface/implementation on Xen. >Actually, the difference derives from the fact that block and network >are indeed different: >- block submits requests that ask the host to transfer from/to >preallocated guest data buffers via dma (request driven) >- net transmits packets that should end up in an skb on the remote >side (two way, push driven) >- net is sensitive to round-trip times, block is not due to the device >plug for request merging > >We tried different access methods for both block and network. We have >selected the current communication mechanics after doing performance >measurements. >I believe for a portable solution we need to develop a set of >primitives for sending signals (read: interrupts) back and forth, for >copying data to guest memory, and for establishing shared memory >between guests and between guest+host. These primitives need to be >implemented for each platform, and paravirtual drivers should build on >top of that. >At this point in time, we are aware that these device drivers don't do >what we'd want for a portable solution. We'll focus on getting the >kernel interfaces to sie/vt/svm proper and portable first. > >so long, >Carsten
Based on the previous discussion and the s390 PV drivers I have more gasoline to pour to the flame: We have a working PV driver with 1Gbit performance. The reasons we don't push it into the kernel are: a. We should perform much better b. It would be a painful task getting all the code review that a complicated network interface should get. c. There's already a PV driver that answers a,b. The Xen's PV network driver is now pushed into the kernel. It is optimized, and support tso. By adding a generic ops calls we can make enjoy all the above. Using Xen's core PV code doesn't imply that we will have their interface {xenstore} the interface creation and tear-down would be kvm specific. They could even have a plain directory structure. ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel