From: Dave Thomas <Dave@...>
Date: 2001-08-18T14:03:10+09:00
Subject: [ruby-talk:19966] Re: Slow file I/O? (newbie)

Bil Kleb <W.L.Kleb@LaRC.NASA.Gov> writes:

> So we were trying to test the speed of mirrored versus non-mirrored
> disks and decided to use Ruby to do the testing.  We wrote a couple
> one-liners to write and read a Gigabyte-sized file of all 1's, viz,
> 
>  File.open("testFile","w") { |f| (2**30).times{f.putc "1"} }

Well, with the best will in the world, Ruby is going to be way, way
slower than C here, if for no other reason than the number of
instructions executed.

However, your test isn't simply measuring the speed of writing to
disks. In both C and Ruby, that putc is going to be buffered in the
underlying library before being written to disk in chunks of a block.

You might want to find the underlying blocksize using
File.stat().blksize, and then use IO#write to write stuff out in
chunks that big.


Regards


Dave