From c77353fd9cdfcc8598c03773d9db0d57fa082cce Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Tue, 17 Sep 2019 17:18:13 -0700
Subject: [PATCH] modules/client/sync/rooms/timeline: Add conditional prefetch
 on down iteration.

---
 modules/client/sync/rooms/timeline.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/modules/client/sync/rooms/timeline.cc b/modules/client/sync/rooms/timeline.cc
index 7472bc34d..bcb0ce48d 100644
--- a/modules/client/sync/rooms/timeline.cc
+++ b/modules/client/sync/rooms/timeline.cc
@@ -248,7 +248,6 @@ ircd::m::sync::_room_timeline_polylog_events(data &data,
 		room
 	};
 
-	ssize_t i(0);
 	const ssize_t limit
 	{
 		data.phased && data.range.first == 0?
@@ -256,6 +255,7 @@ ircd::m::sync::_room_timeline_polylog_events(data &data,
 			ssize_t(limit_default)
 	};
 
+	ssize_t i(0), prefetched(0);
 	for(; it && i <= limit; --it)
 	{
 		event_idx = it.event_idx();
@@ -265,6 +265,9 @@ ircd::m::sync::_room_timeline_polylog_events(data &data,
 		if(event_idx < data.range.first)
 			break;
 
+		if(limit > 1)
+			prefetched += m::prefetch(event_idx);
+
 		++i;
 	}