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Comment by barrkel | Hacker News Reader

I blame I/O. It's pretty fast warmed up.

That seems to be the lesson. Don't worry about a few thousands flops here or there, put your focus on minimizing IO.

I/O is one of my biggest daily pains. Spend some time in Process Explorer on Windows and you can see just how much disk-based I/O the average app is doing. Anti-virus software makes the bad problem worse. It's just like pouring sugar in a gastank. Why isn't more software designed to take advantage, where appropriate, of large amounts of RAM?

Did you see that article on the Varnish site about second-guessing Virtual Memory? "2006 programmng" I think it was.

obligatory HN links:

Varnish dev says second-guessing VM is so 1975: http://news.ycombinator.com/item?id=1554656 OR http://news.ycombinator.com/item?id=1760811

Redis dev says second-guessing VM is elite (and not doing so is so 2006): http://news.ycombinator.com/item?id=1760540

Sometimes I wonder if the OS can put very heavily used files from the FS into RAM. Some software just sucks and keeps pulling the same files over and over...

... and the plus side is, if an application needs the RAM, no harm done, just dump the file from RAM and read it from disk.

Good idea. They already do it.

Specifically: SuperFetch, first seen in Vista: http://en.wikipedia.org/wiki/Windows_Vista_I/O_technologies#...

Or Unix's mmap, which predates Vista by a couple decades. (It was designed around the time of 4.2BSD, i.e., 1983* .) I'd be shocked if Windows hasn't had a similar mechanism for years, as well.

* _The Design and Implementation of the 4.4BSD Operating System_, McKusick et al., p. 29-30.

mmap is not SuperFetch; and memory mapping has been in NT since it started.

What SuperFetch does is collect statistics about files hit by processes when they start up, so it can proactively cache bits of those files, to the point that it can cache files read by processes before those processes are ever started, assuming they are either commonly started or started on a schedule.

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