On Wed, 17 Jun 2015 10:08:28 -0500 (CDT) Christoph Lameter <cl@xxxxxxxxx> wrote: > > Per request of Joonsoo Kim adding kmem debug support. > > > bulk- PREVIOUS - THIS-PATCH > > 1 - 43 cycles(tsc) 10.811 ns - 44 cycles(tsc) 11.236 ns improved -2.3% > > 2 - 27 cycles(tsc) 6.867 ns - 28 cycles(tsc) 7.019 ns improved -3.7% > > 3 - 21 cycles(tsc) 5.496 ns - 22 cycles(tsc) 5.526 ns improved -4.8% > > 4 - 24 cycles(tsc) 6.038 ns - 19 cycles(tsc) 4.786 ns improved 20.8% > > 8 - 17 cycles(tsc) 4.280 ns - 18 cycles(tsc) 4.572 ns improved -5.9% > > 16 - 17 cycles(tsc) 4.483 ns - 18 cycles(tsc) 4.658 ns improved -5.9% > > 30 - 18 cycles(tsc) 4.531 ns - 18 cycles(tsc) 4.568 ns improved 0.0% > > 32 - 58 cycles(tsc) 14.586 ns - 65 cycles(tsc) 16.454 ns improved -12.1% > > 34 - 53 cycles(tsc) 13.391 ns - 63 cycles(tsc) 15.932 ns improved -18.9% > > 48 - 65 cycles(tsc) 16.268 ns - 50 cycles(tsc) 12.506 ns improved 23.1% > > 64 - 53 cycles(tsc) 13.440 ns - 63 cycles(tsc) 15.929 ns improved -18.9% > > 128 - 79 cycles(tsc) 19.899 ns - 86 cycles(tsc) 21.583 ns improved -8.9% > > 158 - 90 cycles(tsc) 22.732 ns - 90 cycles(tsc) 22.552 ns improved 0.0% > > 250 - 95 cycles(tsc) 23.916 ns - 98 cycles(tsc) 24.589 ns improved -3.2% > > Hmmm.... Can we afford these regressions? Do notice the "regression" is mostly within 1 cycle. Which I would not call a regression, given the accuracy of these measurements. The page-border cases 32,34,48,64 cannot be use to assess this. We could look at the assembler code, to see if we can spot the extra instruction that does not get optimized away. -- Best regards, Jesper Dangaard Brouer MSc.CS, Sr. Network Kernel Developer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>