• Dipankar Sarma's avatar
    [PATCH] rcu batch tuning · 21a1ea9e
    Dipankar Sarma authored
    This patch adds new tunables for RCU queue and finished batches.  There are
    two types of controls - number of completed RCU updates invoked in a batch
    (blimit) and monitoring for high rate of incoming RCUs on a cpu (qhimark,
    qlowmark).
    
    By default, the per-cpu batch limit is set to a small value.  If the input
    RCU rate exceeds the high watermark, we do two things - force quiescent
    state on all cpus and set the batch limit of the CPU to INTMAX.  Setting
    batch limit to INTMAX forces all finished RCUs to be processed in one shot.
     If we have more than INTMAX RCUs queued up, then we have bigger problems
    anyway.  Once the incoming queued RCUs fall below the low watermark, the
    batch limit is set to the default.
    Signed-off-by: default avatarDipankar Sarma <dipankar@in.ibm.com>
    Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
    Cc: "David S. Miller" <davem@davemloft.net>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    21a1ea9e
rcupdate.c 16.8 KB