Messages in this thread | | | Date | Wed, 23 Jan 2002 20:20:46 -0800 (PST) | From | Glendon Gross <> | Subject | Re: Low latency for recent kernels |
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Is this patch available for 2.5.2 ? or is it already part of the tree?
On 23 Jan 2002, Robert Love wrote:
> On Wed, 2002-01-23 at 22:48, Dan Maas wrote: > > > Two situations where I would expect low-latency/preemption to have a > > positive effect on responsiveness are 1) when the system is under heavy CPU > > and disk load (e.g. kernel compile); due to the interactive tasks being able > > to run earlier/more often, and 2) when performing UI operations that depend > > on tight synchronization between X/the WM/the X client, particularly opaque > > window resizing. (my theory is that low-latency/preemption results in the > > CPU switching more rapidly or evenly among these processes, reducing the > > perceptible "lag" between the client window and its WM frame) > > This is exactly the area preempt/low-latency helps and I think your > theory is pretty much dead on. > > With preempt-kernel, ideally, an interactive task finds itself runnable > like this: user event causes interrupt, interrupt sets need_resched, on > return from interrupt we cause a preemption of current task (which can > happen whether task is in kernel or userland, now), and schedule the > interactive task onto the CPU. > > This leads to better scheduling fairness and short scheduling latency. > > If you or Havoc are interested in any tests or further work with the > preemptive kernel, I'd be more than willing. Hey, I use GNOME ;) > > Robert Love > > - > 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/ >
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