Eric Dumazet wrote:
Linus Torvalds a écrit :
On Tue, 6 Mar 2007, Eric Dumazet wrote:
I did a user space program, attached to this mail.
I rewrote the reciprocal_div() for i386 so that one multiply is used.
Ok, this is definitely faster on Core 2 as well, so "numbers talk,
bullshit walks". No more objections.
And the numbers were ? :)
(That said, I bet you could do even better for octal and hex numbers,
so if you *really* want to speed things up, you should just make a
special-case routine for each base (there's just three of them), and
you can then also optimize the base-10 thing much better (you can do
two digits at a time by dividing by 100, etc)
Well, given that sprintf() is frequently called only for pipe/sockets
creation, we probably better :
1) wait a very clever idea to suppress individual dentry per
pipe/sockets (no more sprintf() at pipe/socket setup)
2) delay the sprintf() only if needed as you mentioned in a previous
mail (when someone wants ls -l /proc/pid/fd/....), since their dentries
are not anymore inserted in the global dcache hash, they could stay with
a (nul) dname.
Yes, the right thing to do is probably to only generate these strings
when someone tries to list them, not on every socket/pipe/epoll
creation. One can assign a counter and keep it as a binary value at the
start, but create the strings when necessary.
-hpa
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