On Mon, 2007-05-11 at 14:59 +0200, Radu Rendec wrote: > Jarek, thanks for replying my message on the list and pointing it to the > right direction. > > Your example with "1" bits laying on exact nibble boundary is much > easier to analyze than my original example. And your computation seems > to be right: u32_hash_fold() would return 00.f0.00.0f (and would be cut > off to 0f after applying the divisor mask).
Yes, that example i believe would work just fine today as is with no changes. [...] > Jamal, I am aware that any computation on the fast path involves some > performance loss. However, I don't see any speed gain with your patch, > because you just moved the ntohl() call inside u32_hash_fold(). Since > u32_hash_fold() is called unconditionally and the only call is that one > in u32_classify(), htohl() will be called exactly the same number of > times. > Sorry, I didnt mean that to be a better approach - it suffers the same problem as what you posted and infact is just your patch simplified essentially (or my attempt at doing that). A simpler version would be to do something in u32_change() only and nowhere else. Thats what i alluded at using fshift. And even after taking a shower i cant think of a simple way to achieve it. > After almost a week of dealing with this, I still don't think it can be > solved without byte re-ordering. If you guys think my patch is good, I > would be more than glad to send it properly (change the comments as > Jarek suggested and use git). Since I'm quite a newbie with git and > haven't worked with kernel maintainers before, please be patient if it's > not perfect at the first attempt :) What tree/branch should I make the > patch against? > Please try the patch i sent since it is simpler. It is your work more or less - so you should get the credit as author. Use Davem's net-2.6 as basis. If it works send it to him and CC me and i will just wsignoff/ack. If it doesnt work, can you cutdown on the conversion in u32_change() instead and send that? cheers, jamal - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
