* Chris Friesen <cfriesen@xxxxxxxxxx> wrote:
It turns out that disabling CONFIG_DYNAMIC_FTRACE makes the load balancing problem go away and causes all cpus to be used.
With this option enabled, the problem seems to be present as far back as 2.6.27-rc2. (2.6.27-rc1 doesn't compile on my machine, and 2.6.26 doesn't have ftrace).
I have no idea why turning on dynamic ftrace would affect load balancing behaviour, but it's very repeatable. The very first test run after booting works fine, and all successive runs fail to balance properly.
OTOH, what does 'truning on dftrace' exactly mean? Just enabling it in the .config, or also activating it via /debug/tracing/current_tracer?