Il 30/10/2013 20:09, Michael S. Tsirkin ha scritto: > I noticed that srcu_read_lock/unlock both have a memory barrier, > so just by moving srcu_read_unlock earlier we can get rid of > one call to smp_mb(). > > Unsurprisingly, the gain is small but measureable using the unit test > microbenchmark: > before > vmcall 1407 > after > vmcall 1357 > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Across how many runs? Best or average or "all runs were in that ballpark", :) and what's the minimum/maximum before and after the patch? As you say the benefit is not surprising, but the experiments should be documented properly. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
