From 75c470bd659a2638e9bfd7d680ea429ed994382c Mon Sep 17 00:00:00 2001
From: Andrej Babic <andrej.babic@psi.ch>
Date: Thu, 23 Apr 2020 10:15:21 +0200
Subject: [PATCH] Adjust hwm size

---
 sf-buffer/src/sf_replay.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sf-buffer/src/sf_replay.cpp b/sf-buffer/src/sf_replay.cpp
index e4bc89f..4f05343 100644
--- a/sf-buffer/src/sf_replay.cpp
+++ b/sf-buffer/src/sf_replay.cpp
@@ -93,7 +93,8 @@ int main (int argc, char *argv[]) {
 
     auto ctx = zmq_ctx_new();
     auto socket = zmq_socket(ctx, ZMQ_PUSH);
-    int sndhwm = REPLAY_BLOCK_SIZE;
+    // The +1 is important so we pre-load the next chunk.
+    int sndhwm = REPLAY_BLOCK_SIZE + 1;
     if (zmq_setsockopt(socket, ZMQ_SNDHWM, &sndhwm, sizeof(sndhwm)) != 0) {
         throw runtime_error(strerror (errno));
     };