Re: [Lse-tech] Re: [patch] scheduler fix for 1cpu/node case

["Martin J. Bligh" <mbligh@aracnet.com>]

>>> If you want data supporting my assumptions: Ted Ts'o's talk at OLS
>>> shows the necessity to rebalance ASAP (even in try_to_wake_up).
> 
>> If this is the patch I am thinking of, it was the (attached) one I sent
> them,
>> which did a light "push" rebalance at try_to_wake_up.  Calling
> load_balance
>> at try_to_wake_up seems very heavy-weight.  This patch only looks for an
> idle
>> cpu (within the same node) to wake up on before task activation, only if
> the
>> task_rq(p)->nr_running is too long.  So, yes, I do believe this can be
>> important, but I think it's only called for when we have an idle cpu.
> 
> The patch that you sent to Rajan didn't yield any improvement on
> specjappserver so we did not include that  in the ols paper. What
> is described in the ols paper is "calling load-balance" from
> try-to-wake-up. Both calling load-balance from try-to-wakeup and
> the "light push" rebalance at try_to_wake_up are already done in
> Andrea's 0(1) scheduler patch.

Are the balances you're doing on wakeup global or node-local?

M.