Create a new "HAVE_GET_CYCLES" architecture option to specify which architectures provide 64-bits TSC counters readable with get_cycles(). It's principally useful to only enable high-precision tracing code only on such architectures and don't even bother building it on architectures which lack such support. It also requires architectures to provide get_cycles_barrier() and get_cycles_rate(). I mainly use it for the "priority-sifting rwlock" latency tracing code, which traces worse-case latency induced by the locking. It also provides the basic changes needed for the LTTng timestamping infrastructure. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx> CC: David Miller <davem@xxxxxxxxxxxxx> CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> CC: Ingo Molnar <mingo@xxxxxxxxxx> CC: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CC: Steven Rostedt <rostedt@xxxxxxxxxxx> CC: linux-arch@xxxxxxxxxxxxxxx --- init/Kconfig | 10 ++++++++++ 1 file changed, 10 insertions(+) Index: linux.trees.git/init/Kconfig =================================================================== --- linux.trees.git.orig/init/Kconfig 2008-11-07 00:06:07.000000000 -0500 +++ linux.trees.git/init/Kconfig 2008-11-07 00:07:23.000000000 -0500 @@ -330,6 +330,16 @@ config CPUSETS config HAVE_UNSTABLE_SCHED_CLOCK bool +# +# Architectures with a 64-bits get_cycles() should select this. +# They should also define +# get_cycles_barrier() : instruction synchronization barrier if required +# get_cycles_rate() : cycle counter rate, in HZ. If 0, TSC are not synchronized +# across CPUs or their frequency may vary due to frequency scaling. +# +config HAVE_GET_CYCLES + def_bool n + config GROUP_SCHED bool "Group CPU scheduler" depends on EXPERIMENTAL -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
