[lkml]   [2003]   [Jan]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [Lse-tech] Minature NUMA scheduler
On Friday 10 January 2003 17:57, Martin J. Bligh wrote:
> This seems like the right approach to me, apart from the trigger to
> do the cross-node rebalance. I don't believe that has anything to do
> with when we're internally balanced within a node or not, it's
> whether the nodes are balanced relative to each other. I think we should
> just check that every N ticks, looking at node load averages, and do
> a cross-node rebalance if they're "significantly out".

OK, I changed my mind about the trigger and made some experiments with
the cross-node balancer called after every N calls of
load_balance. If we make N tunable, we can even have some dynamics in
case the nodes are unbalanced: make N small if the current node is
less loaded than the average node loads, make N large if the node is
averagely loaded. I'll send the patches in a separate email.

> The NUMA rebalancer
> is obviously completely missing from the current implementation, and
> I expect we'd use mainly Erich's current code to implement that.
> However, it's suprising how well we do with no rebalancer at all,
> apart from the exec-time initial load balance code.

The fact that we're doing fine on kernbench and numa_test/schedbench
is (I think) understandeable. In both benchmarks a process cannot
change its node during its lifetime, therefore has minimal memory
latency. In numa_test the "disturbing" hackbench just cannot move away
any of the tasks from their originating node. Therefore the results
are the best possible.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:32    [W:0.091 / U:63.616 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site