Re: [PATCH 00/23] per device dirty throttling -v8

david
2007-08-09T01:31:05Z

On Thu, 9 Aug 2007, Greg Trounson wrote:

>> Measurements show that noatime helps 20-30% on regular desktop workloads,
>> easily 50% for kernel builds and much more than that (in excess of 100%)
>> for file-read-intense workloads. We cannot just walk past such a _huge_
>> performance impact so easily without even reacting to the performance
>> arguments, and i'm happy Ubuntu picked up noatime,nodiratime and is
>> whipping up the floor with Fedora on the desktop.
>>
>
> Sorry I'm just not seeing those gains here. With my filesystems mounted with
> atime defaults the Quake sources build in 1m28.856s. A test with ls -ltu
> verifies that atime is working as expected. When I remount my filesystems
> with:
> mount [fs] -o remount,noatime,nodiratime
> I get a compile time of 1m23.368s, a mere 6% improvement.
>
> This is on a dual-core Athlon 4200+ box running 2.6.21, so I would have
> thought this to be close to a best-case file I/O test.

what sort of disks does this box have? and what filesystem? slower
disks/filesystems can result in this showing a larger difference.

however 6% is a fairly significant gain.

David Lang