28-mar-2016: Welcome to our new server! Faster and less prone to crashing.

Welcome to the Slackware Documentation Project

Use BFQ IO scheduler

Budget Fair Queueing (BFQ) Storage-I/O Scheduler

  • Why do I want BFQ? -Seems to speed up disk based IO see the Source section for more info.

http://algo.ing.unimo.it/people/paolo/disk_sched/

  • First collect your existing kernel configuration.
    zcat /proc/config.gz > BFQ_CONFIG
  • Next prepare your BFQ_CONFIG file (use vi or nano etc). I like to locate “CONFIG_DEFAULT_CFQ” section and make it look like below. Be careful not to have duplicate lines. I'm thinking there is a better way maybe someone could point it out. Basically add the two lines about BFQ change the existing CONFIG_DEFAULT_CFQ to “is not set” and add “CONFIG_DEFAULT_BFQ=y':
    CONFIG_IOSCHED_BFQ=y
    CONFIG_CGROUP_BFQIO=y
    # CONFIG_DEFAULT_DEADLINE is not set
    # CONFIG_DEFAULT_CFQ is not set
    CONFIG_DEFAULT_BFQ=y

You may not need to manually edit the BFQ_CONFIG. I noticed make oldconfig will prompt you about the patches added.

  • Now grab the code: (I'm using 3.14 in this sample as Slackware-current is currently using 3.14.18)
    VERSION=3.14.0-v7r6 # the version you want
    wget -nd --no-parent --level 1 -r -R "*.html*" --reject $VERSION \
        http://algo.ing.unimo.it/people/paolo/disk_sched/patches/$VERSION
  • Now copy your config file to /usr/src/linux and rename it to .config
    Example: (assuming the config you created above is in your home directory)
    cp $HOME/BFQ_CONFIG /usr/src/linux/.config
  • Next copy these files to /usr/src/linux and then patch (you'll want 0001 to 0003).
    cp ./000* /usr/src/linux;cd /usr/src/linux
    patch -p1 < 0001-block-cgroups-kconfig-build-bits-for-BFQ-v7r6-3.14.patch 
    patch -p1 < 0002-block-introduce-the-BFQ-v7r6-I-O-sched-for-3.14.patch 
    patch -p1 < 0003-block-bfq-add-Early-Queue-Merge-EQM-to-BFQ-v7r6-for-3.14.0.patch
  • cd /usr/src/linux ;make oldconfig ;make -j4 && make modules_install
  • copy bzImage and System.map to boot folder
  • add lilo entry and update lilo.

Sources


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