Virtualization - Dec 2022 - [RFC PATCH v5 0/4] vsock: update tools and error handling

On Tue, Dec 20, 2022 at 07:16:38AM +0000, Arseniy Krasnov
wrote:
>Patchset consists of two parts:
>
>1) Kernel patch
>One patch from Bobby Eshleman. I took single patch from Bobby:
>https://lore.kernel.org/lkml/d81818b868216c774613dd03641fcfe63cc55a45
>.1660362668.git.bobby.eshleman at bytedance.com/ and use only part for
>af_vsock.c, as VMCI and Hyper-V parts were rejected.
>
>I used it, because for SOCK_SEQPACKET big messages handling was broken -
>ENOMEM was returned instead of EMSGSIZE. And anyway, current logic which
>always replaces any error code returned by transport to ENOMEM looks
>strange for me also(for example in EMSGSIZE case it was changed to
>ENOMEM).
>
>2) Tool patches
>Since there is work on several significant updates for vsock(virtio/
>vsock especially): skbuff, DGRAM, zerocopy rx/tx, so I think that this
>patchset will be useful.
>
>This patchset updates vsock tests and tools a little bit. First of all
>it updates test suite: two new tests are added. One test is reworked
>message bound test. Now it is more complex. Instead of sending 1 byte
>messages with one MSG_EOR bit, it sends messages of random length(one
>half of messages are smaller than page size, second half are bigger)
>with random number of MSG_EOR bits set. Receiver also don't know total
>number of messages. Message bounds control is maintained by hash sum
>of messages length calculation. Second test is for SOCK_SEQPACKET - it
>tries to send message with length more than allowed. I think both tests
>will be useful for DGRAM support also.
>
>Third thing that this patchset adds is small utility to test vsock
>performance for both rx and tx. I think this util could be useful as
>'iperf'/'uperf', because:
>1) It is small comparing to 'iperf' or 'uperf', so it very
easy to add
>   new mode or feature to it(especially vsock specific).
>2) It allows to set SO_RCVLOWAT and SO_VM_SOCKETS_BUFFER_SIZE option.
>   Whole throughtput depends on both parameters.
>3) It is located in the kernel source tree, so it could be updated by
>   the same patchset which changes related kernel functionality in vsock.
>
>I used this util very often to check performance of my rx zerocopy
>support(this tool has rx zerocopy support, but not in this patchset).
>
>Here is comparison of outputs from three utils: 'iperf',
'uperf' and
>'vsock_perf'. In all three cases sender was at guest side. rx and
>tx buffers were always 64Kb(because by default 'uperf' uses 8K).
>
>iperf:
>
>   [ ID] Interval           Transfer     Bitrate
>   [  5]   0.00-10.00  sec  12.8 GBytes  11.0 Gbits/sec sender
>   [  5]   0.00-10.00  sec  12.8 GBytes  11.0 Gbits/sec receiver
>
>uperf:
>
>   Total     16.27GB /  11.36(s) =    12.30Gb/s       23455op/s
>
>vsock_perf:
>
>   tx performance: 12.301529 Gbits/s
>   rx performance: 12.288011 Gbits/s
>
>Results are almost same in all three cases.
Thanks for checking this!
>
>Patchset was rebased and tested on skbuff v8 patch from Bobby Eshleman:
>https://lore.kernel.org/netdev/20221215043645.3545127-1-bobby.eshleman at
bytedance.com/
I reviewed all the patches, in the last one there is just to update the 
README, so I think it is ready for net-next (when it will re-open).

Thanks,
Stefano