Messages in this thread | | | Date | Wed, 1 Dec 2021 23:18:36 +0000 | Subject | Re: [RFC 00/12] io_uring zerocopy send | From | Pavel Begunkov <> |
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On 12/1/21 23:07, Martin KaFai Lau wrote: > On Wed, Dec 01, 2021 at 03:35:49PM -0700, David Ahern wrote: >> On 12/1/21 2:51 PM, Martin KaFai Lau wrote: >>> >>> To tx out dummy, I did: >>> #> ip a add 10.0.0.1/24 dev dummy0 >> ^^^^^^^^ >>> >>> #> ip -4 r >>> 10.0.0.0/24 dev dummy0 proto kernel scope link src 10.0.0.1 >>> >>> #> ./send-zc -4 -D 10.0.0.(2) -t 10 udp >> ^^^^^^^^^^ >> >> Pavel's commands have: 'send-zc -4 -D <dummy_ip_addr> -t 10 udp' >> >> I read dummy_ip_addr as the address assigned to dummy0; that's an >> important detail. You are sending to an address on that network, not the >> address assigned to the device, in which case packets are created and >> then dropped by the dummy driver - nothing actually makes it to the server. > Right, I assumed "dropped by dummy driver" is the usual intention > for using dummy, so just in case if it was the intention for > testing tx only. You are right and it seems the intention > of this command is to have server receiving the packets.
I see, it seems we found the misunderstanding:
For dummy device, I indeed was testing only tx part without a server, in my understanding it better approximates an actual fast NIC. I don't think dummy is even capable to pass the data, so was thinking that it's given that there is no receive side, and so no "msg_zerocopy -r".
For localhost testing (with the hack), there was a server verifying data.
>> >>> ip -s link show dev dummy0 >>> 2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 65535 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 >>> link/ether 82:0f:e0:dc:f7:e6 brd ff:ff:ff:ff:ff:ff >>> RX: bytes packets errors dropped missed mcast >>> 0 0 0 0 0 0 >>> TX: bytes packets errors dropped carrier collsns >>> 140800890299 2150397 0 0 0 0 >>> >>
-- Pavel Begunkov
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