Re: Word-at-a-time dcache name accesses (was Re: .. anybody know ofany filesystems that depend on the exact VFS 'namehash' implementation?)

From: david
Date: Fri Mar 02 2012 - 19:17:55 EST


On Fri, 2 Mar 2012, Ted Ts'o wrote:

Stupid question. Your patch requires unaligned accesses to not have a
heavy penalty, right? Wasn't it the case that some generations of x86
had pretty large penalties for aligned accesses? Is that something we
need to worry about?

another stupid question

since the code that it's replaceing did byte-at-a-time access, wouldn't that be at least as bad as the new code?

or did some CPUs have efficient char access, but inefficient unaligned word access?

David Lang
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