In message <[EMAIL PROTECTED]>, Nate Lawson wri
tes:

>> Because 1 syscall and 2 namei calls are faster than 4 syscalls and
>> four namei calls.
>
>Which leaves us back at my previous point which is that something is wrong
>with caching if 4 namei calls (for the SAME name) are so much slower.  A
>great task would be to examine/test namei(), identify why it's not cached
>correctly, and fix the underlying problem.  The syscall boundary crossing
>is NOT significant here.

When you restore a N files, it makes a difference if you need to do
4N syscalls and 4N namei's or just 1N syscalls and 2N nameis.

Caching makes the difference smaller, but the fact remains that
there is a difference.  In particular as N climbs into the range
of millions.

Don't forget that restore uses (and has to!) paths relative to its
root directory, each of the nameis can trivially contain a handful
of component names.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED]         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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