> 2008/1/18, Miklos Szeredi <[EMAIL PROTECTED]>: > > > 4. Performance test was done using the program available from the > > > following link: > > > > > > http://bugzilla.kernel.org/attachment.cgi?id=14493 > > > > > > Result: the impact of the changes was negligible for files of a few > > > hundred megabytes. > > > > Could you also test with ext4 and post some numbers? Afaik, ext4 uses > > nanosecond timestamps, so the time updating code would be exercised > > more during the page faults. > > > > What about performance impact on msync(MS_ASYNC)? Could you please do > > some measurment of that as well? > > Did a quick test on an ext4 partition. This is how it looks like:
Thanks for running these tests. I was more interested in the slowdown on ext4 (checked with the above mentioned program). Can you do such a test as well, and post resulting times with and without the patch? > Table 1. Reference platforms. > > ------------------------------------------------------------ > | | HP-UX/PA-RISC | HP-UX/Itanium | FreeBSD | > ------------------------------------------------------------ > | First run | 263405 usec | 202283 usec | 90 SECONDS | > ------------------------------------------------------------ > | Second run | 262253 usec | 172837 usec | 90 SECONDS | > ------------------------------------------------------------ > | Third run | 238465 usec | 238465 usec | 90 SECONDS | > ------------------------------------------------------------ > > It looks like FreeBSD is a clear outsider here. Note that FreeBSD > showed an almost liner depencence of the time spent in the > msync(MS_ASYNC) call on the file size. > > Table 2. The Qemu system. File size is 512M. > > --------------------------------------------------- > | | Before the patch | After the patch | > --------------------------------------------------- > | First run | 35 usec | 5852 usec | > --------------------------------------------------- > | Second run | 35 usec | 4444 usec | > --------------------------------------------------- > | Third run | 35 usec | 6330 usec | > --------------------------------------------------- Interesting. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
