Re: 2.6.12 Performance problems
From: Ben Greear <hidden>
Date: 2005-08-25 06:34:56
Also in:
lkml
Possibly related (same subject, not in this thread)
- 2005-08-21 · Re: 2.6.12 Performance problems · Andrew Morton <hidden>
Danial Thom wrote:
quoted hunk ↗ jump to hunk
--- Ben Greear <greearb@candelatech.com> wrote:quoted
Danial Thom wrote:quoted
I think the concensus is that 2.6 has madetradequoted
offs that lower raw throughput, which is whataquoted
networking device needs. So as a router or network appliance, 2.6 seems less suitable. Arawquoted
bridging test on a 2.0Ghz operton system: FreeBSD 4.9: Drops no packets at 900K pps Linux 2.4.24: Starts dropping packets at 350Kppsquoted
Linux 2.6.12: Starts dropping packets at 100Kpps I ran some quick tests using kernel 2.6.11, 1ms tick (HZ=1000), SMP kernel. Hardware is P-IV 3.0Ghz + HT on a new SuperMicro motherboard with 64/133Mhz PCI-X bus. NIC is dual Intel pro/1000. Kernel is close to stock 2.6.11. I used brctl to create a bridge with the two GigE adapters in it and used pktgen to stream traffic through it (250kpps in one direction, 1kpps in the other.) I see a reasonable amount of drops at 250kpps (60 byte packets): about 60,000,000 packets received, 20,700 dropped.
I get slightly worse performance on this system when running RH9 with kernel 2.4.29 (my hacks, HZ=1000, SMP). Tried increasing e1000 descriptors to 2048 tx and rx, but that didn't help, or at least not much. Will try some other tunings, but I doubt it will affect performance enough to come close to the discrepency that you show between 2.4 and 2.6 kernels... I tried copying a 500MB CDROM to HD on my RH9 system, and only 6kpps of the 250kpps get through the bridge...btw. Ben -- Ben Greear [off-list ref] Candela Technologies Inc http://www.candelatech.com