Hi,
I am developing an application (a distributed cache server) that will
be using UDP protocol to send/receive many small packets at high rate
and I am looking for a zero copy networking solution.
First I evaluated the PACKET_MMAP . It is a small patch to kernel
code, uses no system calls to receive packets and can send multiple
packets with one system call. However it is NOT a true zero copy,
since it does a copy inside the kernel, line 762 of af_packet.c:
skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
Then I checked PF_RING kernel module. It has much more features than
just send/receive packets, has much larger development community, and
it supports true zero copy with DNA aware NICs. I have checked the
source for pf_ring module and it is big, many lines of code should be
executed at runtime. Also it needs 1 syscall for every send/receive.
Correct me if i am wrong please.
What would you recommend me to use for my application in order to
achieve fast networking? If I use PACKET_MMAP I will not get a true
zero copy but I will be avoiding issuing too much syscalls and saving
on code size, thus gaining a little bit of speed.
If I use PF_RING I will have a true zero copy but more instructions
will be executed and more syscalls issued, so maybe there would be no
big difference in speed?
Will appreciate any comment.
Regards
Nulik
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