On Mon, 2006-02-27 at 17:32 +0100, Dag Bakke wrote: > I have been playing with a couple of laptops with GbE interfaces, and > iperf. (Two Dell Latitude D600 connected back-to-back.) > I was actually quite happy to get 600 Mbps of TCP traffic through the cable. > Until I realised that my GbE interface appears to be capable of running > at 66 MHz, thus having the potential for higher throughput than > initially thought. > > 02:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5705M > Gigabit Ethernet (rev 01) > Subsystem: Dell Latitude D400 > Flags: bus master, 66MHz, medium devsel, latency 32, IRQ 11
66MHz comes from PCI status register (offset 0x6) bit 5 which means the device is capable of 66MHz. The actual bus speed may be 33 or 66 depending on the bus. > Memory at faff0000 (64-bit, non-prefetchable) [size=64K] > Capabilities: [48] Power Management version 2 > Capabilities: [50] Vital Product Data > Capabilities: [58] Message Signalled Interrupts: 64bit+ > Queue=0/3 Enable- > > Yet, my kernel spews: > eth0: Tigon3 [partno(BCM95705A50) rev 3001 PHY(5705)] (PCI:33MHz:32-bit) This is the actual bus speed determined by the driver. > 10/100/1000BaseT Ethernet 00:0f:1f:bd:38:06 > eth0: RXcsums[1] LinkChgREG[1] MIirq[1] ASF[0] Split[0] WireSpeed[1] > TSOcap[1] > eth0: dma_rwctrl[763f0000] > > > Is there anything I can do to increase the bandwidth further, or is this > as far as the host bridge will take me? I have enabled CONFIG_PCI_MSI, > but it doesn't look like it makes any difference. > Do the intel chipsets support MSI? The driver will not enable MSI on 5705M because of hardware bugs so it won't make any difference. You might try enabling TSO with ethtool -K. It may or may not increase throughput but should decrease your CPU utilization. > > Using 2.6.16-rc4. > > 00:00.0 Host bridge: Intel Corporation 82855PM Processor to I/O > Controller (rev 03) > Flags: bus master, fast devsel, latency 0 > Memory at e0000000 (32-bit, prefetchable) [size=128M] > Capabilities: [e4] Vendor Specific Information > Capabilities: [a0] AGP version 2.0 > > 00:01.0 PCI bridge: Intel Corporation 82855PM Processor to AGP > Controller (rev 03) (prog-if 00 [Normal decode]) > Flags: bus master, 66MHz, fast devsel, latency 32 > Bus: primary=00, secondary=01, subordinate=01, sec-latency=32 > I/O behind bridge: 0000c000-0000cfff > Memory behind bridge: fc000000-fdffffff > Prefetchable memory behind bridge: e8000000-efffffff > > 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 81) > (prog-if 00 [Normal decode]) > Flags: bus master, fast devsel, latency 0 > Bus: primary=00, secondary=02, subordinate=02, sec-latency=32 > I/O behind bridge: 0000d000-0000efff > Memory behind bridge: f6000000-fbffffff > Prefetchable memory behind bridge: 30000000-33ffffff > > > Some interpretations and explanations would be very much appreciated. > > > Dag B > - > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
