On 10/8/2010 3:18 PM, Richard Scobie wrote: > Testing continues, reply below: > > Dan Williams wrote: >> [ adding Dave, Maciej ] >> >> On 10/4/2010 1:13 PM, Brandeburg, Jesse wrote: >>> >>> Dan might be able to further help with the ioatdma portion, this sounds >>> like a possible regression in 4.00 ioatdma? >> >> Smells that way. I'm traveling internationally this week, but I can try >> to reproduce this on my 5400 next week when I'm back (unless Dave or >> Maciej have a chance to take a look). Question below: >> >>> >>> On Sat, 2 Oct 2010, Richard Scobie wrote: >>> >>>> I have a Tyan S5396 5400 based board, which has been running >>>> 2.6.30.10-105.2.23.fc11.x86_64and has a PRO/1000 PT (82571EB) Quad >>>> adapter, along with two onboard 80003ES2LAN adapters. >>>> >>>> This has performed fine with the ioatdma loaded and the BIOS is the >>>> latest. >>>> >>>> dca service started, version 1.8 >>>> ioatdma 0000:00:0f.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 >>>> ioatdma 0000:00:0f.0: setting latency timer to 64 >>>> ioatdma 0000:00:0f.0: Intel(R) I/OAT DMA Engine found, 4 channels, >>>> device version 0x20, driver version 3.64 >>>> alloc irq_desc for 62 on cpu 0 node 0 >>>> alloc kstat_irqs on cpu 0 node 0 >>>> ioatdma 0000:00:0f.0: irq 62 for MSI/MSI-X >>>> alloc irq_desc for 63 on cpu 0 node 0 >>>> alloc kstat_irqs on cpu 0 node 0 >>>> ioatdma 0000:00:0f.0: irq 63 for MSI/MSI-X >>>> alloc irq_desc for 64 on cpu 0 node 0 >>>> alloc kstat_irqs on cpu 0 node 0 >>>> ioatdma 0000:00:0f.0: irq 64 for MSI/MSI-X >>>> alloc irq_desc for 65 on cpu 0 node 0 >>>> alloc kstat_irqs on cpu 0 node 0 >>>> ioatdma 0000:00:0f.0: irq 65 for MSI/MSI-X >>>> ioatdma 0000:00:0f.0: DCA is disabled in BIOS >>> >>> hm, I think this note above is critical that it is missing from the >>> below. >>> >>>> I have just updated to 2.6.35.7 stable and with ioatdma loaded, samba RX >>>> performance drops from normal levels, to about 500kB/s with the smbd >>>> process at 100% CPU. >>> >>> does netstat -s show it all to be from retransmits or SACKs? >> >> I assume smbd normally does not consume 100% cpu. Can you send the >> output of: >> >> perf record -a sleep 5; perf report >> >> ...while the bad performance is occurring. That might give a clue as to >> what is tanking the performance. > > Not sure if the 300k file will make it as an attachment, so here are the > first entries in the report. Let me know if you'd still like the file: > > > perf report --sort comm,dso,symbol | head -50 > # Events: 7K cycles > # > # Overhead Command Shared Object Symbol > # ........ ............... .................... ...... > # > 58.34% smbd [ioatdma] [k] ioat_tx_status > 39.19% smbd [kernel.kallsyms] [k] tcp_service_net_dma
Ok, this looks like we are spending a lot of time waiting for the dma engine... but it's not immediately clear why. It looks like I can reproduce this with a simple iperf test. I'll see if I can bisect when this was introduced. witout ioatdma: # iperf -c <test system> -l 256k -w 256k -P 16 -t 7200 [..] [SUM] 0.0-31.7 sec 3.45 GBytes 934 Mbits/sec with ioatdma: # iperf -c <test system> -l 256k -w 256k -P 16 -t 7200 [..] [SUM] 0.0-41.3 sec 364 MBytes 73.9 Mbits/sec -- Dan ------------------------------------------------------------------------------ Beautiful is writing same markup. Internet Explorer 9 supports standards for HTML5, CSS3, SVG 1.1, ECMAScript5, and DOM L2 & L3. Spend less time writing and rewriting code and more time creating great experiences on the web. Be a part of the beta today. http://p.sf.net/sfu/beautyoftheweb _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
