I've just had some surprising results when running hard drive performance tests in Ubuntu 12.10 vs Linux Mint Debian Edition, which I'm dual-booting on the same machine (and the same hard drive).
I was running some tests for a Ruby application I'm working on, and the test suite came out at 19 minutes 19 seconds on Ubuntu 12.10. The test suite runs much more quickly on a range of other machines, so I decided to reboot into LMDE and run it again. It came out at 9 minutes 19 seconds on LMDE.
This was quite surprising - the Ubuntu installation runs tests only half as fast on the exact same machine - so I ran hdparm in order to see what the disk read speeds were (the limiting factor in these tests is likely to be how fast the tests can class-load themselves, and load fixture data from disk).
hdparm says the following:
/dev/sda: Timing cached reads: 1900 MB in 2.00 seconds = 950.19 MB/sec Timing buffered disk reads: 248 MB in 3.01 seconds = 82.29 MB/sec
/dev/sda: Timing cached reads: 7588 MB in 2.00 seconds = 3796.70 MB/sec Timing buffered disk reads: 216 MB in 3.01 seconds = 71.73 MB/sec
The difference in test execution speed is explained here. LMDE is reading cached info nearly 4 times as quickly off the disk.
Are there hdparm settings that I can use to speed up the Ubuntu installation? Are there any known issues affecting hard drive performance that I can work around in some way?