On Sun, 2009-02-15 at 11:04 +0100, Ingo Molnar wrote: > qemu-sy-4237 has been scheduled away, and the system appeared to have done > nothing in the meantime. That's not something that really looks like a > scheduler regression - there is nothing the scheduler can do if KVM > decides to block a task. > > It would be nice to enhance this single-CPU trace some more - to more > surgically see what is going on. Firstly, absolute timestamps would be > nice: > > echo funcgraph-abstime > trace_options > echo funcgraph-proc > trace_options > > as it's a bit hard to see the global timescale of events. I was going to try and grab the trace with absolute timestamps tonight, but that option doesn't seem to be available in Linus' current kernel. flexo:/sys/kernel/debug/tracing# echo 0 > tracing_enabled flexo:/sys/kernel/debug/tracing# echo function_graph > current_tracer flexo:/sys/kernel/debug/tracing# echo funcgraph-proc > trace_options flexo:/sys/kernel/debug/tracing# echo funcgraph-abstime > trace_options -su: echo: write error: Invalid argument flexo:/sys/kernel/debug/tracing# cat trace_options print-parent nosym-offset nosym-addr noverbose noraw nohex nobin noblock nostacktrace nosched-tree ftrace_printk noftrace_preempt nobranch annotate nouserstacktrace nosym-userobj noprintk-msg-only nofuncgraph-overrun funcgraph-cpu funcgraph-overhead funcgraph-proc flexo:/sys/kernel/debug/tracing# uname -a Linux flexo 2.6.29-rc5-00299-gadfafef #6 SMP Sun Feb 22 20:09:37 CST 2009 x86_64 GNU/Linux What am I missing? Cheers, Kevin. -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
