Subject: Re: RAW access to files
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 12/13/2001 03:22:18
>> As for the memcpy, I'd rather memcpy from buffers than wait for a
>> disk transfer - even a transfer that hits the disk's track cache.
> given that choice, I'd choose the memory-to-memory copy as well.

Gee, what a surprise. :-)

> but in the contexts where direct i/o is really targetted, the choice
> is between "wait for a disk tranfer" and "wait for a disk transfer
> and then also do the memory-to-memory", since the data is not going
> to be in the file system's cache.

That's why I've been trying to find a paradigm that lets the OS do
readahead, so that it _can_ be in the cache, and the choice _is_ then
between a memcpy and a disk transfer.

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