From: Davidlohr Bueso <dave@xxxxxxxxxxxx> Subject: lib/interval_tree_test.c: allow users to limit scope of endpoint Add a 'max_endpoint' parameter such that users may easily limit the size of the intervals that are randomly generated. Link: http://lkml.kernel.org/r/20170518174936.20265-4-dave@xxxxxxxxxxxx Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/interval_tree_test.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff -puN lib/interval_tree_test.c~lib-interval_tree_test-allow-users-to-limit-scope-of-endpoint lib/interval_tree_test.c --- a/lib/interval_tree_test.c~lib-interval_tree_test-allow-users-to-limit-scope-of-endpoint +++ a/lib/interval_tree_test.c @@ -16,6 +16,7 @@ __param(int, perf_loops, 100000, "Number __param(int, nsearches, 100, "Number of searches to the interval tree"); __param(int, search_loops, 10000, "Number of iterations searching the tree"); +__param(uint, max_endpoint, ~0, "Largest value for the interval's endpoint"); static struct rb_root root = RB_ROOT; static struct interval_tree_node *nodes = NULL; @@ -40,18 +41,20 @@ static void init(void) int i; for (i = 0; i < nnodes; i++) { - u32 a = prandom_u32_state(&rnd); - u32 b = prandom_u32_state(&rnd); - if (a <= b) { - nodes[i].start = a; - nodes[i].last = b; - } else { - nodes[i].start = b; - nodes[i].last = a; - } + u32 b = (prandom_u32_state(&rnd) >> 4) % max_endpoint; + u32 a = (prandom_u32_state(&rnd) >> 4) % b; + + nodes[i].start = a; + nodes[i].last = b; } + + /* + * Limit the search scope to what the user defined. + * Otherwise we are merely measuring empty walks, + * which is pointless. + */ for (i = 0; i < nsearches; i++) - queries[i] = prandom_u32_state(&rnd); + queries[i] = (prandom_u32_state(&rnd) >> 4) % max_endpoint; } static int interval_tree_test_init(void) _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
