Messages in this thread |  | | Date | Tue, 25 Sep 2001 16:20:17 -0300 | From | Chris Newton <> | Subject | excessive interrupts on network cards |
| |
Hi,
I 'think' the number of interrupts being generated for the network traffic I monitor, is excessive. Having talked quikly with Donald Becker, he indicated that I should be seeing a little less than the number of RX/TX packets/s on a wire, in terms of interrupts/s. That, however, is not what I am seeing. I am seeing 3 times as many interrupts/s as I am seeing packets/s.
I have used three network devices to look at the stream I am monitoring, and it is usually aorund 5K packet/s IN, and 5K out, fed full duplex into a single 3Com 3c982 (2.4.10 kernel reports that anyways). However, watching:
'procinfo -D', reports on the order of 30,000 interrupts per second.
This page:
http://www.scyld.com/network/3c509.html
has a snipet:
"some other device or device driver hogging the bus or disabling interrupts. Check /proc/interrupts for excessive interrupt counts. The timer tick interrupt should always be incrementing faster than the others. "
Well, looking at this machine, since it booted 57 minutes ago:
[root@phantom /proc]# more interrupts CPU0 CPU1 0: 172754 171041 IO-APIC-edge timer 1: 0 3 IO-APIC-edge keyboard 2: 0 0 XT-PIC cascade 14: 2 2 IO-APIC-edge ide0 16: 87361 87539 IO-APIC-level eth2 20: 6798697 6799977 IO-APIC-level eth0 21: 0 0 IO-APIC-level eth1 30: 11837 11806 IO-APIC-level aic7xxx 31: 199418 199209 IO-APIC-level aic7xxx NMI: 0 0 LOC: 343669 343708 ERR: 0 MIS: 0
In 57 minutes, that ethernet card has generated: 14,000,459 interrupts.
Isn't this excessive?
I also have a different brand card on board... an intel ether express pro. So... I swapped the cables so that the intel card would see that network stream. Well, it caused even more interrupts per second. (more like 40K).
I have tried kernel 2.4.9, 2.4.2 (redhat 7.1 version), and just now, 2.4.10, all SMP builds, on a dual 1 GHz PIII, with 1 GB of SDRAM, Adaptec 7899 Ultra160 controller, two 3c982 netcards and one onboard intel etherexpress pro 100 cards.
Guess my question is, first of.. is this normal?
- 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/
|  |