Klaus Schmidinger wrote:
Emil Naepflein wrote:
On Mon, 10 Oct 2005 09:54:56 +0300, Marko Mäkelä wrote:
On Mon, Oct 10, 2005 at 06:52:12AM +0200, Emil Naepflein wrote:
This is pretty useless on my system because the loss of responsiveness is mostly caused by the disk accesses and not by cpu usage.
Are you sure that DMA disk transfers are enabled? If not, the copying with programmed I/O (PIO) will consume CPU.
As I wrote, there is no problem with cpu usage. And DMA is enabled as I use a Promise SX6000 controller (SCSI interface). The main problem is that the cutting thread reads and writes the data through the buffer cache and purges useful data from the buffer cache. Any disk access when using the menu then is delayed considerably. This is with a 2.4 kernel. The 2.6 kernel behaves much better in this regard.
I'm currently in the process of adopting Ralf Müller's patch to avoid trashing the disk cache. Maybe that will help.
2.6.13+ also supports ionice. That could help to not starve other processes accessing the disk. AFAIK it's on a per process level though so the cutting thread would need to be turned into to a separate cutting process.
cu Ludwig