• X
    alinux: mm: add proc interface to control context readahead · 2e38a0f2
    Xiaoguang Wang 提交于
    For some workloads whose io activities are mostly random, context
    readahead feature can introduce unnecessary io read operations, which
    will impact app's performance. Context readahead's algorithm is
    straightforward and not that smart.
    
    This patch adds "/proc/sys/vm/enable_context_readahead" to control
    whether to disable or enable this feature. Currently we enable context
    readahead default, user can echo 0 to /proc/sys/vm/enable_context_readahead
    to disable context readahead.
    
    We also have tested mongodb's performance in 'random point select' case,
    With context readahead enabled:
      mongodb eps 12409
    With context readahead disabled:
      mongodb eps 14443
    About 16% performance improvement.
    Signed-off-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
    Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
    2e38a0f2
vm.txt 33.5 KB