On 07/11/2017 11:56 AM, Vlastimil Babka wrote: > On 07/11/2017 08:03 AM, Michal Hocko wrote: >> On Tue 11-07-17 09:58:42, Anshuman Khandual wrote: >>>> here. This is hardly something that would save many cycles in a >>>> relatively cold path. >>> Though I have not done any detailed instruction level measurement, >>> there is a reduction in real and system amount of time to execute >>> the test with and without the patch. >>> >>> Without the patch >>> >>> real 0m2.100s >>> user 0m0.162s >>> sys 0m1.937s >>> >>> With this patch >>> >>> real 0m0.928s >>> user 0m0.161s >>> sys 0m0.756s >> Are you telling me that two if conditions cause more than a second >> difference? That sounds suspicious. > It's removing also a call to get_unmapped_area(), AFAICS. That means a > vma search? I believe removing this function is responsible for the increase in speed of the test execution. -- 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>
