Messages in this thread | | | Subject | Re: Does a kernel assisted file system reorder make sense? | From | Andi Kleen <> | Date | Sun, 15 Nov 2009 14:37:28 +0100 |
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Christian Volkmann <haveaniceday@cv-sv.de> writes:
> Hi, > > I just have read some articles about faster booting systems > (Ubuntu 9.10) , SSD, hard disks, latency and seek times... > > Due to this I have some ideas which I like to discuss. > I am for sure not the first with this idea, but I do not > find any discussion about it. :)
Most modern distributions these days use some variant of prefetch at boot.
> Shouldn't it be possible for the kernel to provide an ordered > loaded block list read from disk ? This could be used for a kind > of "forced reorder" for a file system tool.
Typically it's enough to just collect all the blocks read at boot and then prefetch them in order to minimize seeks. That's what various distributions do, typically by using blktrace to generate these lists and then suitable prefetch daemons. Sometimes it's also just done at the file level, because that's often also good enough.
The suse preload package also has a e2remapblocks for remapping inside individual files, but I don't think it helps all that much. At least it's not used by default.
-Andi
-- ak@linux.intel.com -- Speaking for myself only.
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