Hi all, After compiling kernels for a while I found out why the Fedora's kernel works for me: it is built without PAE support. I've bisected Ubuntu' and Fedora's .config files and it turnes out that CONFIG_HIGHMEM4G=y "fixes" my issue ;) .
After that I rebooted my machine with default Ubuntu kernel (PAE) and 16Gb RAM, not 32GB, and it also "fixed" my issue ;) After that I built a kernel with PAE, 32GB but with CONFIG_VMSPLIT_1G=y , and again, it really fixed my issue (but it is incompatible with binary drivers, see documentation; and my fglrx didn't work). To wit: Linux kernel doesn't work well with 32bit, PAE and >=32 Gb RAM. (I even saw such statemets somewhere on the Net.) Am I right? If so, I think Ubuntu documentation should state it explicitly. ** Summary changed: - IO limit 1.2 MB/s for 32bit ubuntu (ACPI issues) + IO limit 1.2 MB/s for 32bit ubuntu (PAE, 32 Gb RAM) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1264707 Title: IO limit 1.2 MB/s for 32bit ubuntu (PAE, 32 Gb RAM) Status in “linux” package in Ubuntu: Incomplete Bug description: I recently installed a new motherboard Asus M5A99FX PRO R2.0 and found out that IO speed is very low; i.e. the dd command output: dd if=/dev/zero of=/tmp/output bs=8k count=1000k ^C13885+0 records in 13885+0 records out 113745920 bytes (114 MB) copied, 99.6639 s, 1.1 MB/s This issue is reproducing with my new SSD (with ext4), my USB drives and my hard disk (with ext4) from Ubuntu i386, 13.04 and 13.10. Such a speed is not ok, awfully slow. When I run two or more the same dd commands simultaneously, I have 1,2 Mb/s for every process. WORKAROUNDs: - turn off ACPI services, see more at https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1264707/comments/18 - Use the amd64 version ProblemType: Bug DistroRelease: Ubuntu 13.10 Package: linux-image-3.11.0-12-generic 3.11.0-12.19 ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3 Uname: Linux 3.11.0-12-generic i686 ApportVersion: 2.12.5-0ubuntu2 Architecture: i386 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC2: ubuntu 4507 F.... pulseaudio /dev/snd/controlC1: ubuntu 4507 F.... pulseaudio /dev/snd/controlC0: ubuntu 4507 F.... pulseaudio CasperVersion: 1.336ubuntu1 Date: Sat Dec 28 15:56:33 2013 IwConfig: lo no wireless extensions. eth0 no wireless extensions. LiveMediaBuild: Ubuntu 13.10 "Saucy Salamander" - Release i386 (20131016.1) MachineType: To be filled by O.E.M. To be filled by O.E.M. MarkForUpload: True ProcEnviron: LANGUAGE=en_US TERM=xterm PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 radeondrmfb ProcKernelCmdLine: noprompt cdrom-detect/try-usb=true persistent file=/cdrom/preseed/hostname.seed boot=casper initrd=/casper/initrd.lz quiet splash -- maybe-ubiquity PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied No PulseAudio daemon running, or not running as session daemon. RelatedPackageVersions: linux-restricted-modules-3.11.0-12-generic N/A linux-backports-modules-3.11.0-12-generic N/A linux-firmware 1.116 RfKill: SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 04/10/2013 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 1708 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: M5A99FX PRO R2.0 dmi.board.vendor: ASUSTeK COMPUTER INC. dmi.board.version: Rev 1.xx dmi.chassis.asset.tag: To Be Filled By O.E.M. dmi.chassis.type: 3 dmi.chassis.vendor: To Be Filled By O.E.M. dmi.chassis.version: To Be Filled By O.E.M. dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1708:bd04/10/2013:svnTobefilledbyO.E.M.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnASUSTeKCOMPUTERINC.:rnM5A99FXPROR2.0:rvrRev1.xx:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.: dmi.product.name: To be filled by O.E.M. dmi.product.version: To be filled by O.E.M. dmi.sys.vendor: To be filled by O.E.M. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1264707/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
