On Fri, Oct 14, 2016 at 08:58:22AM +0000, Koehrer Mathias (ETAS/ESW5) wrote: > @@ -753,7 +756,9 @@ u32 igb_rd32(struct e1000_hw *hw, u32 re > if (E1000_REMOVED(hw_addr)) > return ~value; > > + trace_igb(801); > value = readl(&hw_addr[reg]); > + trace_igb(802); Nothing prevents this code from being preempted between the two trace points, and so you can't be sure whether the time delta in the trace is caused by the PCIe read stalling or not. Thanks, Richard -- 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
