Hello all, I have just set up my first xenomai system, and though I believe I have followed most of the guidelines, if I run latency it sits at around 8uS max, until I run something to stress the system (e.g. startx, or killing the x server) when it jumps to 700-800uS.
I wonder if this is to do with graphics? I have set "NoAccel" in the driver section of Xorg.conf (I am using fbdev). I also notice that latencies go massive (e.g. 4200uS) the first time I run glxgears. "glxinfo" reports "Direct rendering: no". This is a core 2 duo system (MEN F19P cPCI) with ICH9M-SFF chipset. I am running debian (lenny) and have followed the guide in the wiki (here: http://www.xenomai.org/index.php/Building_Debian_packages) to install kernel 2.6.32.15 and xenomai 2.5.4. I have made the following selections for kernel configuration in order to try and prevent latency issues: Processor type and features: Enable interrupt pipeline Enable high resolution timer support Disable dell laptop support Processor family --> Core 2/Newer Xeon Preemption model --> Preemptible kernel (low latency desktop) Bus options (PCI etc): Disable PCI express hotplug driver Disable message signalled interrupts (MSI and MSI-X) Disable PCCard (PCMCIA/Cardbus support) Disable support for PCI hotplug Device drivers: Disable Memory Technology Device (MTD) support Disable Fusion MPT device support Disable I20 device support Disable ISDN support Power management options (ACPUI, APM): Disable ACPI (Advanced Configuration and Power Interface) Support --> Processor Disable CPU Frequency Scaling Disable CPU idle PM support Disable Power Managment Support Real-time sub-system: Enable Machine--> SMI workaround Enable Machine--> globally disable SMI I have read through this: http://svn.gna.org/svn/xenomai/trunk/TROUBLESHOOTING and tried to find anything relevant. I am booting from an on board compact flash via USB. I wondered if this could be the problem. Output of hdparm: hdparm -v /dev/sda readonly = 0 (off) readahead = 256 (on) geometry = 1024/255/63, sectors = 31227840, start = 0 hdparm -acdgkmur /dev/sda HDIO_GET_MULTICOUNT failed: Invalid argument HDIO_GET_32BIT failed: Invalid argument HDIO_GET_UNMASKINTR failed: Invalid argument HDIO_GET_DMA failed: Invaid argument HDIO_GET_KEEPSETTINGS failed: Invalid argument (reast of output same as hdparm -v) hdparm -t /dev/sda /dev/sda: Timing buffered disk reads: 100MB in 3.01 seconds = 33.24 MB/sec hdparm -T /dev/sda /dev/sda: Timing cached reads: 11006 MB in 2.00 seconds = 5503.00 MB/sec Then I did cat /proc/scsi/scsi: Host: scsi4 Channel: 00 Id: 00 Lun: 00 Vendor: Generic Model: Flash HS-CF Rev: 1.68 Type: Direct-Access ANSI SCSI revision: 00 Also, this embedded system has a lot of configuration options in the BIOS (more than I have seen on any other system). Some seem like they could be very useful but are currently unusable (e.g. if I set "SMI handler" to off, the system will no longer boot from compact flash). There are also other options that might be relevant. I have tried playing with them, but am not even sure what some are and the manual is quite cryptic: IDE Controller settings "HDC configure as" Options: "IDE", "RAID", "AHCI" USB Configuration "USB Legacy" Enable/Disable "EHCI1" Enable/Disable "EHCI2" " "UHCI1" " "UHCI2" ... "UHCI5" "Per-Port Control2" Enable/Disable "USB Pre-fetch Feature" Enable/Disable "USB Pre-fetch Time" 2ms/4ms "USB HC Alignment" Enable/Disable Chipset Configuration "CRID/SRID" Enable/Disable "Port 80h Cycles" LPC bus/PCI bus "DMI Link ASPM Control" Enable/Disable "Automatic ASMO" Auto/Manual "ASPM L0s Support" Enable/Disable "ASPM L0sL1 Support" Enable/Disable "VT-d" Enable/Disable ACPI Table/Feature Control "FACP - C2 Latency Value" Enable/Disable "FACP - C3 Latency Value" Enable/Disable "FACP - RTC S4 Wakeup" Enable/Disable "APIC - IO APIC Mode" Enable/Disable "HPET - HPET Support" Enable/Disable PCI Express Root Port 1/2/3/4/5/6 Settings "ASPM" Enable/Disable "Automatic ASPM" Auto/Manual "ASPM L0s" Root&Endpoint Ports/ Disabled/ Root Port Only/ Endpoint port Only "ASPM L1" Enable/Disable "URR" Enable/Disable "FER" Enable/Disable "NFER" Enable/Disable "CER" Enable/Disable "CTO" Enable/Disable "SEFE" Enable/Disable "SENFE" Enable/Disable "SECE" Enable/Disable "PME Interrupt" Enable/Disable "PME SCI" Enable/Disable "Hot Plug SCI" Enable/Disable Advanced CPU Control "P-States" Enable/Disable "CMP Support" Enable/Disable "Vanderpool Technology" Enable/Disable "SMRR Support" Auto/Disable "C-States" Enable/Disable "Enhanced C-States" Enable/Disable "C-State Pop Up Mode" Enable/Disable "C-State Pop Down Mode" Enable/Disable "C4 Exit Timing Mode" Fast/Slow/Default/Force Slow "DeepC4" Enable/Disable "Hard C4E" Enable/Disable "Enable C6" Enable/Disable "EMTTM" Enable/Disable "Bi-directional PROCHOT#" Enable/Disable "ACPI 3.0 T-States" Enable/Disable "DTS" Enable/Disable" ... (lots more options that I am not sure what they really are for!) Platfoirm Power Management "Storage Break Event" Enable/Disable "PCIE Break Event" Enable/Disable "PCI Break Event" Enable/Disable "EHCI Break Event" Enable/Disable "UHCI Break Event" Enable/Disable "HDA Break Event" Enable/Disable "ACPI S3" Enable/Disable So, could anyone suggest what I might try to improve the system? Sorry for the torrent of information... I thought it better to give as much info as I could think of than to not provide enough to make a diagnosis! Thanks, Edward Robbins Control Systems Engineer Oxford Technologies Ltd UKAEA Culham Joint European Torus, Remote Handling Division
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