Re: Attempt at laptop-mode for 2.6.0

From: Bart Samwel
Date: Tue Dec 23 2003 - 13:52:04 EST


Jens Axboe wrote:
Even though I don't own a laptop, I find it very irritating that my hard
drive is active so much. Wanting to fix this, I found the Jens Axboe's
"laptop-mode" patch. Unfortunately it hadn't been ported to Linux
2.6.0 yet, and I'm using that as my primary kernel now. I gave porting it a shot, and here is the result. I'm running it right now, and my hard drive has been spun down for the complete time I have been writing this message. Still, I'm not sure whether it really works as advertised. :) The reason is that my PC is also a mail server for my personal e-mail, and I receive e-mails more than once every 10 minutes (fscking spam!). Still, the tests that I've done seem to indicate that it works.

Thanks for getting this started. I'm not particularly fond of the
behaviourial changes you made, I guess most are due to it being
incomplete?

Is it only the block dirtyings that you're missing, or is there more? I might have used an old 2.4 patch as reference -- what was the latest version again?

The block dirtying is the most interesting aspect of the dump
functionality, reporting WRITEs don't give you the info you need
to fix your setup.

OK, that depends on your point of view. At this point it weren't the WRITEs that were interesting to me, it were the READs. The WRITEs just came as a bonus. The reason: what bugged me during development were the programs that read new data from disk, and I wanted to find out what to turn off in order to keep the disk from spinning up all the time. And when the disk DID spin up, I wanted to know if it was my fault or if it was some daemon messing up my tests again. This is due to my not actually working on a laptop but on a home server machine. :) I guess that when you're going for disk-spindowns of longer than 10 minutes (which is what the block dirtying dumps are for, presumably?) dirtyings start to become interesting. I'll see if I can port that bit as well, shouldn't be that much work.

Bart

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