Messages in this thread | | | Date | Mon, 09 Aug 2004 10:57:41 +0100 | From | Paulo Marques <> | Subject | Re: ide-cs using 100% CPU |
| |
Hamie wrote: > Alan Cox wrote: > >> On Gwe, 2004-08-06 at 20:33, Hamie wrote: >> >> >>> Is 100% CPU not excessive? IIRC my PIII-750 used to use less CPU >>> doing the same job as quick, or even slightly faster... >>> >> >> >> PCMCIA IDE is PIO only so it burns CPU. This is one case where >> hyperthreading is nice. Cardbus IDE is a lot better but very little >> exists and we don't currently support hotplug IDE controllers. >> >> >> > > Ah right. But would a CF memory card be cardbus anyway?
I've never seen a CF card that supported DMA (and I've worked with several brands). Compact Flash cards have several modes of operation and only one of this modes is "IDE-compatible".
> >>> And should it not use system CPU rather than user CPU? >>> >> >> >> Yes - but figure out please if the kernel or userspace is getting that >> wrong ;) >> >> >> > > My apologies. It was gkrellm leading me up the garden path on that > one... Copying about 100MB from a 512MB CF card (25+ photos from my > camera) vmstat 5 reports 4% usercpu, 96% system cpu. And the response on > the system is sluggish to say the least. (Moving the pointer in X is > painful :). gkrell meanwhile on it's cpu graph shows about 30% system, > and the rest as userCPU. No idea why, I guess till I find out I'll just > regard gkrellm's cpu graph as a waste of space (To differentiate system > & user cpu anyway :).
I think this is more of a scheduler/priorities problem. Maybe all the work that is being done with staircase / low-latency will help you on this :)
-- Paulo Marques - www.grupopie.com "In a world without walls and fences who needs windows and gates?" - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |