On 2006/11/16 16:25, Christian Weisgerber wrote: > > > I just don't understand how there can be a difference factor of 10. > > factor of 100. > (Are you really sure a minute has 100 seconds?)
No I'm not, come to think of it... > > softdep mount option? this will slow down creation/removal of > > large numbers of files. > > Please, you are not a dog, that Pavlovian response is nonsense. Ah, I didn't realise how little was written by 'make depend'. For some operations, having WCE and softdep off does make a difference approaching this of order of magnitude. Knowing that some drives ship with WCE turned off (e.g. at least those supplied with some HP DL385 and Fujitsu-Siemens servers), it's a quick and simple thing to check which accounts for performance differences on some operations of this sort of order of magnitude. I just tried untarring ports.tar.gz on some F-S box: WCE, softdep no WCE, softdep WCE, no softdep no WCE, no softdep 0m49.29s 13m8.72s 1m51.58s 30m9.95s > Strictly speaking, you should DISABLE write caching when using > softupdates. Surely this applies without softupdates too, though? It also relies on the drive doing what you tell it, which isn't guaranteed, especially with consumer drives optimised for performance in benchmarks (aiui some drives always enable write-cache no matter what you tell them; with these, providing they're ATA-6 compliant, you may force it with READ VERIFY SECTOR/S).
