Here are some patches that I have been working on a few months ago. For some applications (e.g. FTQ) you can see the jitter that is introduced by the timer tick in the result data set. Therefore the task was to completely disable the timer tick or at least reduce the impact on the application. This patchset is reusing the infrastructure that disables the timer tick during idle periods to disable it as well when SCHED_FIFO tasks are executed. The results of the FTQ workload show that the timer tick is getting disabled long periods but the impact of a single interruption seems to increase. Possible, this is due to the fact that the timer tick needs to be enabled again during interrupts. Other known issues: - Currently the time accounting is totally broken but that was not the primary focus. Rants? Thoughts? Complaints? Jan Jan Blunck (4): ftrace: Add events for tracing timer interrupts ftrace: Add events for tracing tick start and stop Disable scheduler tick when we are running SCHED_FIFO tasks ftrace: Add argument to tick start/stop tracing arch/x86/kernel/apic/apic.c | 4 +++ arch/x86/kernel/time.c | 5 ++++ include/linux/tick.h | 14 +++++++++++- include/trace/events/irq.h | 38 ++++++++++++++++++++++++++++++++++ include/trace/events/sched.h | 46 ++++++++++++++++++++++++++++++++++++++++++ kernel/sched_rt.c | 23 +++++++++++++++++++++ kernel/softirq.c | 5 ++++ kernel/time/tick-sched.c | 40 ++++++++++++++++++++++++----------- 8 files changed, 160 insertions(+), 15 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
