From 1d90a685eb75a56648d7dd22c704a1a6da516de9 Mon Sep 17 00:00:00 2001 From: Petr Holasek Date: Thu, 16 Apr 2015 17:38:19 +0200 Subject: [PATCH] perf bench numa: Fix immediate meeting of convergence condition This patch fixes the race in the beginning of benchmark run when some threads hasn't got assigned curr_cpu yet so they don't occur in nodes-of-process stats and benchmark concludes that all remaining threads are converged already. The race can be reproduced with small amount of threads and some bigger amount of shared process memory, e.g. one process, two threads and 5GB of process memory. Signed-off-by: Petr Holasek Reviewed-by: Ingo Molnar Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1429198699-25039-4-git-send-email-pholasek@redhat.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/bench/numa.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c index cd872e9c3a9c..ba5efa4710b5 100644 --- a/tools/perf/bench/numa.c +++ b/tools/perf/bench/numa.c @@ -828,6 +828,9 @@ static int count_process_nodes(int process_nr) td = g->threads + task_nr; node = numa_node_of_cpu(td->curr_cpu); + if (node < 0) /* curr_cpu was likely still -1 */ + return 0; + node_present[node] = 1; } @@ -882,6 +885,11 @@ static void calc_convergence_compression(int *strong) for (p = 0; p < g->p.nr_proc; p++) { unsigned int nodes = count_process_nodes(p); + if (!nodes) { + *strong = 0; + return; + } + nodes_min = min(nodes, nodes_min); nodes_max = max(nodes, nodes_max); } -- 2.20.1