Hello, Since some weeks, I'm facing a problem with the computer I'm using. His results to the cyclictest are very bad, and the max latency is about 38ms. Yes. "ms". I didn't know yet if it was only a software problem or if it was linked to hardware, so I installed a debian distribution, with RT kernel (3.0.0-1-rt-amd64) on an external SDD, and tried it on more than one computer. The results with other computers were very good (about 40us maximum), but when I tried on this computer, or on others computers with the same hardware: the problem was here. There is a first maximum at about 19ms, and after that about 38ms. > # /dev/cpu_dma_latency set to 0us > policy: other/other: loadavg: 0.51 0.18 0.09 1/499 25409 > > T: 0 (22080) P: 0 I:1000 C: 34849 Min: 3 Act: 3 Avg: 69 Max: 37864 Yesterday, I posted a patch that allowed me to test the hardware latency of my computer, and here are the results (still very bad...) : > root@USBnux:/home/xaf/RT/rt-tests# ./hwlatdetect --threshold=1 --report=/home/xaf/hwlat_report > > hwlatdetect: test duration 120 seconds > parameters: > Latency threshold: 1us > > Sample window: 1000000us > Sample width: 500000us > Non-sampling period: 500000us > Output File: /home/xaf/hwlat_report >Starting test >test finished >Max Latency: 38136us >Samples recorded: 45 >Samples exceeding threshold: 45 >sample data written to /home/xaf/hwlat_report and the content of the hwlat_report file : > 1319575592.0802426354 19061 > 1319575593.0806426299 2 > 1319575608.0898425572 19065 > 1319575610.0906425467 19063 > 1319575616.0930425175 2 > 1319575620.0950424982 19048 > 1319575622.0958424885 2 > 1319575627.0010424686 2 > 1319575629.0026424590 19063 > 1319575630.0030424546 19048 > 1319575633.0046424390 19063 > 1319575634.0050424344 19037 > 1319575637.0062424197 38125 > 1319575641.0078423997 19082 > 1319575642.0082423947 19062 > 1319575649.0110423608 19066 > 1319575650.0114423561 19050 > 1319575651.0118423511 19048 > 1319575655.0138423311 2 > 1319575659.0154423121 19069 > 1319575661.0162423015 19072 > 1319575662.0166422975 19049 > 1319575664.0174422870 19068 > 1319575665.0178422825 19063 > 1319575666.0182422774 19059 > 1319575668.0190422679 19055 > 1319575670.0198422577 19051 > 1319575671.0202422531 19060 > 1319575674.0222422384 2 > 1319575676.0230422288 38106 > 1319575680.0246422092 38136 > 1319575682.0254421988 19045 > 1319575683.0258421943 19045 > 1319575685.0266421842 19058 > 1319575689.0282421645 2 > 1319575695.0318421354 2 > 1319575696.0322421303 19050 > 1319575697.0326421258 19085 > 1319575699.0342421159 19049 > 1319575701.0366421057 19039 > 1319575702.0386420994 19049 > 1319575704.0390420911 19065 > 1319575706.0398420818 19053 > 1319575707.0402420761 19036 > 1319575710.0446420605 2 I really have no idea from where the problem could be. And I need your lights to help me. Here is the lspci of the incriminated computer : > 00:00.0 Host bridge: Intel Corporation 5000X Chipset Memory Controller Hub (rev 31) > 00:02.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x4 Port 2 (rev 31) > 00:03.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x4 Port 3 (rev 31) > 00:04.0 PCI bridge: Intel Corporation 5000X Chipset PCI Express x16 Port 4-7 (rev 31) > 00:08.0 System peripheral: Intel Corporation 5000 Series Chipset DMA Engine (rev 31) > 00:10.0 Host bridge: Intel Corporation 5000 Series Chipset FSB Registers (rev 31) > 00:10.1 Host bridge: Intel Corporation 5000 Series Chipset FSB Registers (rev 31) > 00:10.2 Host bridge: Intel Corporation 5000 Series Chipset FSB Registers (rev 31) > 00:11.0 Host bridge: Intel Corporation 5000 Series Chipset Reserved Registers (rev 31) > 00:13.0 Host bridge: Intel Corporation 5000 Series Chipset Reserved Registers (rev 31) > 00:15.0 Host bridge: Intel Corporation 5000 Series Chipset FBD Registers (rev 31) > 00:16.0 Host bridge: Intel Corporation 5000 Series Chipset FBD Registers (rev 31) > 00:1b.0 Audio device: Intel Corporation 631xESB/632xESB High Definition Audio Controller (rev 09) > 00:1d.0 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB Controller #1 (rev 09) > 00:1d.1 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB Controller #2 (rev 09) > 00:1d.2 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB Controller #3 (rev 09) > 00:1d.3 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB Controller #4 (rev 09) > 00:1d.7 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset EHCI USB2 Controller (rev 09) > 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev d9) > 00:1f.0 ISA bridge: Intel Corporation 631xESB/632xESB/3100 Chipset LPC Interface Controller (rev 09) > 00:1f.1 IDE interface: Intel Corporation 631xESB/632xESB IDE Controller (rev 09) > 00:1f.2 SATA controller: Intel Corporation 631xESB/632xESB SATA AHCI Controller (rev 09) > 00:1f.3 SMBus: Intel Corporation 631xESB/632xESB/3100 Chipset SMBus Controller (rev 09) > 01:00.0 VGA compatible controller: nVidia Corporation GT215 [GeForce GT 240] (rev a2) > 01:00.1 Audio device: nVidia Corporation High Definition Audio Controller (rev a1) > 02:00.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Upstream Port (rev 01) > 02:00.3 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express to PCI-X Bridge (rev 01) > 03:00.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Downstream Port E1 (rev 01) > 03:02.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Downstream Port E3 (rev 01) > 05:00.0 Ethernet controller: Intel Corporation 80003ES2LAN Gigabit Ethernet Controller (Copper) (rev 01) > 05:00.1 Ethernet controller: Intel Corporation 80003ES2LAN Gigabit Ethernet Controller (Copper) (rev 01) Thank you for your help. Raphaël -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
