[Qemu-devel] [PATCH V4 3/5] block: Enable the new throttling code in the block layer.

2013-08-08 Thread Benoît Canet
tip: Do not ever use the cfg scheduler in the guest with this code. It gives incorrect throttling. Signed-off-by: Benoit Canet ben...@irqsave.net --- block.c | 351 ++--- block/qapi.c | 21 ++- blockdev.c

Re: [Qemu-devel] [PATCH V4 3/5] block: Enable the new throttling code in the block layer.

2013-08-08 Thread Paolo Bonzini
Il 08/08/2013 16:29, Benoît Canet ha scritto: tip: Do not ever use the cfg scheduler in the guest with this code. It gives incorrect throttling. This is not really accurate; the cfq scheduler reorders reads and writes to have longer bursts, and these sometimes exceed the rate you set. I

Re: [Qemu-devel] [PATCH V4 3/5] block: Enable the new throttling code in the block layer.

2013-08-08 Thread Benoît Canet
Also, it would be better to have a workaround for this. Perhaps we could simply make the default value of max nonzero? In the old throttling code the slice time is 0.1s, so perhaps we could see what happens with max=0.1*avg. This gives correct results with cfg with some little auto