Messages in this thread |  | | Subject | Re: Gigabit/SMP performance problem | From | "Avery Fay" <> | Date | Mon, 6 Jan 2003 15:29:13 -0500 |
| |
Well, judging by the fact that a UP kernel can route more traffic (and consequently more interrupts p/s) than an SMP kernel, I think that one cpu can probably handle all of the interrupts. Really the issue I'm trying to solve is not routing performance, but rather the fact that SMP routing performance is worse while using twice the cpu time (2 cpu's at around 95% vs. 1 at around 95%).
Avery Fay
"Martin J. Bligh" <mbligh@aracnet.com> 01/03/2003 04:36 PM
To: Avery Fay <avery_fay@symantec.com> cc: linux-kernel@vger.kernel.org Subject: Re: Gigabit/SMP performance problem
P3's distributed interrupts round-robin amongst cpus. P4's send everything to CPU 0. If you put irq_balance on, it'll spread them around, but any given interrupt is still only handled by one CPU (as far as I understand the code). If you hammer one adaptor, does that generate more interrupts than 1 cpu can handle? (turn irq balance off by sticking a return at the top of balance_irq, and hammer one link, see how much CPU power that burns).
M.
- 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/
|  |