Messages in this thread | | | From | Christian <> | Subject | Sluggish system responsiveness on I/O | Date | Sat, 18 Nov 2006 14:12:29 +0100 |
| |
Hello lkml!
Im currently testing 2.6.19-rc5-mm1. Everything works really fine except the little wart with bad multimedia interactivity with a kernel compiling in the background. So I tried to narrow it down as much as possible.
I did several find's,dd's and cats in parrallel and watched four instances of glxgears and also played a little enemy-territory. The interactivity was very good, in fact no loss of interactivity at all. This was contrary to what I believed the whole time. The loss of interactivity has nothing to do with heavy I/O. In fact it happens only when I run a task which is I/O and CPU heavy at the same time. That means a single kernel compile (with -j1) is able to harm interactivity with glxgears and enemy-territory, but fully loading my three disks does no harm at all.
So I tried to nice the make and see what happens:
nice 5 make -j4: Seems to make no difference. Heavy stuttering in glxgears and et nice 10 make -j4: Somewhat better but still unusable with et
everything above nice 15 is usable. nice 19 has full interactivity, that means you can't make out a difference between no load and kernel compile while playing enemy-territory.
I suspect that it has something to do with the priority boost for I/O hogs. But if this is a "general" scheduler problem, then why aren't more people complaining about this?
-Christian - 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/
| |