19/02/2014 17:46, Didier Pallard: > According to Intel Developer's Manual: > > "The RDTSC instruction is not a serializing instruction. It does not > necessarily wait until all previous instructions have been executed before > reading the counter. Simi- larly, subsequent instructions may begin > execution before the read operation is performed. If software requires > RDTSC to be executed only after all previous instruc- tions have completed > locally, it can either use RDTSCP (if the processor supports that > instruction) or execute the sequence LFENCE;RDTSC." > > So add a rte_rdtsc_precise function that do a memory barrier before rdtsc > to synchronize operations and ensure that the TSC read is done at the > expected place. > > Signed-off-by: Didier Pallard <didier.pallard at 6wind.com> > --- > > Call rte_mb() and rte_rdtsc() rather than duplicating rte_rdtsc function. > Use r/w memory barrier instead of lfence to serialize both load and stores.
Acked and applied. Thanks to all -- Thomas
