• Peter Zijlstra's avatar
    sched/deadline: Remove the sysctl_sched_dl knobs · 1724813d
    Peter Zijlstra authored
    Remove the deadline specific sysctls for now. The problem with them is
    that the interaction with the exisiting rt knobs is nearly impossible
    to get right.
    The current (as per before this patch) situation is that the rt and dl
    bandwidth is completely separate and we enforce rt+dl < 100%. This is
    undesirable because this means that the rt default of 95% leaves us
    hardly any room, even though dl tasks are saver than rt tasks.
    Another proposed solution was (a discarted patch) to have the dl
    bandwidth be a fraction of the rt bandwidth. This is highly
    confusing imo.
    Furthermore neither proposal is consistent with the situation we
    actually want; which is rt tasks ran from a dl server. In which case
    the rt bandwidth is a direct subset of dl.
    So whichever way we go, the introduction of dl controls at this point
    is painful. Therefore remove them and instead share the rt budget.
    This means that for now the rt knobs are used for dl admission control
    and the dl runtime is accounted against the rt runtime. I realise that
    this isn't entirely desirable either; but whatever we do we appear to
    need to change the interface later, so better have a small interface
    for now.
    Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
    Link: http://lkml.kernel.org/n/tip-zpyqbqds1r0vyxtxza1e7rdc@git.kernel.org
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
core.c 187 KB