Thread (19 messages) flat view 19 messages, 6 authors, 2016-01-14

Re: [PATCH net-next] hv_netvsc: don't make assumptions on struct flow_keys layout

From: One Thousand Gnomes <hidden>
Date: 2016-01-14 17:53:30
Also in: lkml

These results for Toeplitz are not plausible. Given random input you
cannot expect any hash function to produce such uniform results. I
suspect either your input data is biased or how your applying the hash
is.

When I run 64 random IPv4 3-tuples through Toeplitz and Jenkins I get
something more reasonable:
IPv4 address patterns are not random. Nothing like it. A long long time
ago we did do a bunch of tuning for network hashes using big porn site
data sets. Random it was not.

It's probably hard to repeat that exercise now with geo specific routing,
and all the front end caches and redirectors on big sites but I'd
strongly suggest random input is not a good test, and also that you need
to worry more about hash attacks than perfect distributions.

Alan
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help