On Sun, 27 Dec 2009 at 14:50, jim owens wrote: > And I don't even care about comparing 2 filesystems, I only care about > timing 2 versions of code in the single filesystem I am working on, > and forgetting about hardware cache effects has screwed me there. Not me, I'm comparing filesystems - and when the HBA or whatever plays tricks and "sync" doesn't flush all the data, it'll do so for every tested filesystem. Of course, filesystem could handle "sync" differently, and they probably do, hence the different times they take to complete. That's what my tests are about: timing comparision (does that still fall under the "benchmark" category?), not functional comparision. That's left as a task for the reader of these results: "hm, filesystem xy is so much faster when doing foo, why is that? And am I willing to sacrifice e.g. proper syncs to gain more speed?" > So unless you are sure you have no hardware cache effects... > "the comparison still stands" is *false*. Again, I don't argue with "hardware caches will have effects", but that's not the point of these tests. Of course hardware is different, but filesystems are too and I'm testing filesystems (on the same hardware). Christian. -- BOFH excuse #278: The Dilithium Crystals need to be rotated. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
