On Sat, 2009-04-18 at 11:33 +0530, Amit Shah wrote: > On (Fri) Apr 17 2009 [16:13:42], Theodore Tso wrote: > > On Fri, Apr 17, 2009 at 11:39:06PM +0530, Amit Shah wrote: > > > # 4GiB file, kernel 9f76208c33984ab777eace5d07a4e36e88703e02 + ext3-guarded > > > > > > filesystem posix-fallocate mmap chunk-4096 chunk-8192 > > > ext3-guarded 85 97 459 90 > > > ext3-writeback 86 95 140 94 > > > ext3-ordered 86 96 277 95 > > > > > > Running the test in single user mode, I get the following results: > > > > > > # 4GiB file, kernel 9f76208c33984ab777eace5d07a4e36e88703e02 + ext3-guarded > > > > > > filesystem posix-fallocate mmap chunk-4096 chunk-8192 > > > ext3-guarded 84 86 163 91 > > > ext3-writeback 84 88 217 91 > > > ext3-ordered 84 86 226 91 > > > > > > The difference between guarded and writeback in chunk-4096 looking at > > your desktop timings and your single user times is.... surprising. > > Surely. I re-ran the guarded test immediately after that one and got a > time of 353s with the desktop. Another run much latergave me a 189s time, > so it seems to vary quite a lot. Initially when I was getting high > numbers, I thought it could be related to the IO scheduler but looks like > it's just some background tasks trying to get cpu or io time. Of course, > the whole system becomes sluggish once these tests start. > > > In particular, the fact that the guarded time is 3 times longer than > > ext3-writeback when the desktop is running, and 20% faster in single > > user mode. Are these results reproducible? And do you have any > > thoughts as to what might be causing them? > > I initially thought there was something but I also got lower numbers > (189s), so I can't really say what it is even though I call sync before > starting the tests. Probably because you're swapping heavily, and that is perturbing your test? With my setup, 3GB ram + 2GB swap, I can't even run the 4GB test without an mmap() failure/abort, but with 3GB size, box swaps insanely. (If I drop file size to 2GB, I see zip difference for all three mounts modes. 4k chunk time is ~27s for all three. Actually, all numbers emitted are around 27s.) -Mike -- 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
