File read-ahead and Linux-1.3.85

Matti E Aarnio (mea@mea.cc.utu.fi)
Mon, 8 Apr 1996 22:39:28 +0300 (EET DST)


> Linux-1.3.85 also does
....
> - file read-ahead code update

This should have speeded up the system, right ?
(Such claim was made by the author of that patch..)

-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
Lnx1380 100 3221 60.4 2973 19.9 1150 13.9 2300 44.1 2844 12.9 45.9 2.3
Lnx1384 180 2395 43.4 2714 17.2 1339 16.7 2519 47.2 3253 14.6 69.2 2.9
Lnx1385 180 2520 44.9 3204 19.8 1258 16.1 2721 56.6 3220 16.0 70.1 3.0

This machine is a 266 MHz Alpha-XL with integrated NCR 53C810, and
Seagate ST31230N SCSI-disk. At the last two tests the system had
128 MB memory, while with the first one there was propably 32 MB memory.

My point, either we are limited by the disk, or perhaps the NCR-driver
is not as good as it could be... The read-ahead does not help noticeably.
...
> Now, go test it out to see if I broke something else while the above got
> fixed..
> Linus

/Matti Aarnio <mea@utu.fi>