Ingo Molnar wrote on Saturday, July 30, 2005 12:19 AM > * Nick Piggin <[EMAIL PROTECTED]> wrote: > > > > here's an updated patch. It handles one more detail: on SCHED_SMT we > > > should check the idleness of siblings too. Benchmark numbers still > > > look good. > > > > Maybe. Ken hasn't measured the effect of wake balancing in 2.6.13, > > which is quite a lot different to that found in 2.6.12. > > > > I don't really like having a hard cutoff like that -wake balancing can > > be important for IO workloads, though I haven't measured for a long > > time. [...] > > well, i have measured it, and it was a win for just about everything > that is not idle, and even for an IPC (SysV semaphores) half-idle > workload i've measured a 3% gain. No performance loss in tbench either, > which is clearly the most sensitive to affine/passive balancing. But i'd > like to see what Ken's (and others') numbers are. > > the hard cutoff also has the benefit that it allows us to potentially > make wakeup migration _more_ agressive in the future. So instead of > having to think about weakening it due to the tradeoffs present in e.g. > Ken's workload, we can actually make it stronger.
Sorry it took us a while to get the experiment done on our large db setup. This patch has the same effectiveness compare to turning off both SD_WAKE_BALANCE and SD_WAKE_AFFINE, (+2.2% on db OLTP workload). We like it a lot. - Ken - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
