Commit 1d90a685 authored Apr 16, 2015 by Petr Holasek Committed by Arnaldo Carvalho de Melo Apr 27, 2015

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 <pholasek@redhat.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1429198699-25039-4-git-send-email-pholasek@redhat.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 24f1ced1

tools/perf/bench/numa.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -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);
		}