Messages in this thread | | | Date | Mon, 20 Mar 2006 22:24:10 +0800 | From | Wu Fengguang <> | Subject | Re: [patch] latency-tracing-v2.6.16 |
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On Mon, Mar 20, 2006 at 11:13:07AM +0100, Ingo Molnar wrote: > i've released the latency-tracer patch for v2.6.16: > > http://redhat.com/~mingo/latency-tracing-patches/latency-tracing-v2.6.16.patch
Thanks, it helps a lot :)
> max scheduling latencies can be tracked via the enabling of > CONFIG_WAKEUP_TIMING. Tracking can be started via the resetting of the > max latency: > > echo 0 > /proc/sys/kernel/preempt_max_latency > > if CONFIG_LATENCY_TRACE is enabled too then an execution trace will be > automatically generated as well, accessible via /proc/latency_trace.
In fact that is not enough. In include/asm-i386/timex.h, get_cycles() is defined as
static inline cycles_t get_cycles (void) { unsigned long long ret=0; #ifndef CONFIG_X86_TSC if (!cpu_has_tsc) return 0; #endif #if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC) rdtscll(ret); #endif return ret; }
If one (as I did at the first attempt) selects a CPU type of "586/K5/5x86/6x86/6x86MX", he will get nothing from /proc/latency_trace.
So does it make sense to add dependency lines like the following one?
depends on (!X86_32 || X86_GENERIC || X86_TSC)
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