Messages in this thread | | | From | Marc-Christian Petersen <> | Subject | Re: 2.4.22pre6aa1 | Date | Tue, 22 Jul 2003 15:34:16 +0200 |
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On Friday 18 July 2003 00:50, Andrea Arcangeli wrote:
Hi Andrea,
> Can you try to change include/linux/blkdev.h like this: > -#define MAX_QUEUE_SECTORS (4 << (20 - 9)) /* 4 mbytes when full sized */ > +#define MAX_QUEUE_SECTORS (16 << (20 - 9)) /* 4 mbytes when full sized */ > This will raise the queue from 4 to 16M. That is the first(/only) thing > that can explain a drop in performnace while doing contigous I/O. > However I didn't expect it to make a difference, or at least not so > relevant. > If this doesn't help at all, it might not be an elevator/blkdev thing. > At least on my machines the contigous I/O still at the same speed. well, it doesn't help at all. I/O gets more worse with that change. (8mb/s less). How can this happen? *wondering*
> You also where the only one reporting a loss of performance with > elevator-lowlatency, it could be still the same problem that you've > seen at that time. The only one? Surely not. Also Con tested your elevator-lowlatency and we both saw performance degration :)
> can you try with data=writeback (or ext2) or hdparm -W1 and see if you > can still see the same delta between the two kernels? (careful with -W1 > as it invalidates journaling) Yes, I'll do it later this day.
Sorry for my late reply. I've been very busy.
ciao, Marc
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