From edd325e3385841edca25fe92531b86a4e3c9f279 Mon Sep 17 00:00:00 2001
From: Eric Fischer <enf@pobox.com>
Date: Tue, 22 Dec 2015 10:33:08 -0800
Subject: [PATCH] Round the number of threads to use down to a power of 2

Since other calculations depend on this being true
---
 geojson.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/geojson.c b/geojson.c
index 6248b57..f968cfc 100644
--- a/geojson.c
+++ b/geojson.c
@@ -70,6 +70,9 @@ void init_cpus() {
 		CPUS = 1;
 	}
 
+	// Round down to a power of 2
+	CPUS = 1 << (int) (log(CPUS) / log(2));
+
 	TEMP_FILES = 64;
 	struct rlimit rl;
 	if (getrlimit(RLIMIT_NOFILE, &rl) != 0) {