Messages in this thread | | | From | (bill davidsen) | Subject | Re: [PATCH] 2.6.0 batch scheduling, HT aware | Date | 30 Dec 2003 00:29:58 GMT |
| |
In article <200312272215.01563.kernel@kolivas.org>, Con Kolivas <kernel@kolivas.org> wrote: | On Sat, 27 Dec 2003 22:09, Pavel Machek wrote: | > So... even on normal SMP, | > "task-on-other-cpu-slows-down-task-on-this-cpu" effect exists. Okay, | > it is not as visible as on HT machine (50% slowdown), but its | > definitely there. | | Sure but I think we're getting pedantic here. The problem is really simple - a | uniprocessor HT desktop booted in SMP mode feels half the speed while running | setiathome (or video encoding or whatever cpu bound task) compared to booting | it in UP mode. So, ironically, enabling the HT makes the machine feel slower | when running multiple tasks. And there will be a heck of a lot of these in | the future.
Let me put forth a thought, without a solution. In the case you describe, what is needed, and not provided in hardware, is a way to do priority within the CPU, so in the case of a contested resource there is a way to ensure the process we wish wins.
Since that seems unavailable in Intel, do other CPUs do better (or different)? -- bill davidsen <davidsen@tmr.com> CTO, TMR Associates, Inc Doing interesting things with little computers since 1979. - 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/
| |