From 44b239c501762cbee4ac0d218b144c937e642098 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers3@gmail.com>
Date: Wed, 1 Jan 2014 23:11:59 -0600
Subject: [PATCH] compress_parallel.c:  Use 1 buffer per thread if chunks are
 big

---
 src/compress_parallel.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/compress_parallel.c b/src/compress_parallel.c
index fa7f5dde..6cd306c2 100644
--- a/src/compress_parallel.c
+++ b/src/compress_parallel.c
@@ -423,8 +423,15 @@ new_parallel_chunk_compressor(int out_ctype, u32 out_chunk_size,
 
 	desired_num_threads = num_threads;
 
-	chunks_per_msg = MAX_CHUNKS_PER_MSG;
-	msgs_per_thread = 2;
+	if (out_chunk_size < ((u32)1 << 23)) {
+		chunks_per_msg = MAX_CHUNKS_PER_MSG;
+		msgs_per_thread = 2;
+	} else {
+		/* Big chunks: Just have one buffer per thread --- more would
+		 * just waste memory.  */
+		chunks_per_msg = 1;
+		msgs_per_thread = 1;
+	}
 	for (;;) {
 		approx_mem_required =
 			(u64)chunks_per_msg *
-- 
2.43.0