On 8/18/2012 2:05 PM, Poul-Henning Kamp wrote:
In message <5030033b.4060...@feral.com>, Matthew Jacob writes:
On 8/18/2012 1:32 PM, Poul-Henning Kamp wrote:
Shouldn't we at least increase it to pagesize ?
What data suggests to you it would be better at pagesize?
The number of system calls to fwrite() a big file ?
What evidence would there be that it would hurt ?
I am normally not this conservative, but I see this as "why make a
change"? If you're concerned about performance, you won't be using
fwrite, you'll use O_DIRECT and do your own alignment. But I see your point.
One could vaguely argue that a 4K BUFSIZ will put at risk more data on
crashes needlessly. One could also vaguely say that the write syscall
isn't expensive in and of itself, and that there might be a measurable
difference for having to copy 4K (unaligned) than 1K (unaligned) to
kernel space for disposition.
Wasn't there just a recent discussion about running 1.x binaries? One
reason we can do things like that is basic constants don't change very
often. I believe the last time I saw BUFSIZ change was from BSD 2.9 to
BSD 4.0, but I probably misremember that.
If you're going to talk about making a change to defaults, the default
MAXPHYS and DLFTPHYS have been undersized for years now.
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