Hi Dan, On Mon, 25 Jun 2007, Dan Williams wrote:
> Yes you are right, ARM does not flush L1 when prev==next in switch_mm. > > > Perhaps something else is at fault here. > > > I'll try and dig a bit deeper... BTW: static int __init iop_adma_init (void) { + iop_adma_workqueue = create_workqueue("iop-adma"); + if (!iop_adma_workqueue) + return -ENODEV; + Could you also try upping the prio of all the "iop-adma" threads? You should see thread names such as (on SMP) "iop-adma/0", "iop-adma/1" ... "iop-adma/N" where N = # of CPUs - 1. do a "chrt -p -f 98 <pid>" once for each of the thread's PIDs. The chrt can be found in the package "util-linux" on Red Hat / Fedora, and in schedutils on Debian. It just dawned on me that workqueues don't run at a high priority by default. So it's funny that I'm running all my current tasklets as a low priority work queues :-) But that can certainly be a cause of high latency. I need to update my patches to make the workqueue thread a higher priority. All benchmarks on this patch have been using a low priority work queue. I also don't see any nice API to have the priority set for a workqueue thread from within the kernel. Looks like one needs to be added, otherwise, I need to have the wrapper dig into the workqueue structs to find the thread that handles the workqueue. Thanks, -- Steve - 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/