Messages in this thread | | | Date | Tue, 06 Mar 2007 23:13:49 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [patch v2] epoll use a single inode ... |
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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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