diff --git a/docs/manual.rst b/docs/manual.rst
index b1040ea61..a67166230 100644
--- a/docs/manual.rst
+++ b/docs/manual.rst
@@ -5292,7 +5292,8 @@ upload or download rate performance.
 			outstanding_disk_buffer_limit_reached,
 			outstanding_request_limit_reached,
 			upload_limit_too_low,
-			download_limit_too_low
+			download_limit_too_low,
+			send_buffer_watermark_too_low
 		};
 
 		performance_warning_t warning_code;
diff --git a/include/libtorrent/alert_types.hpp b/include/libtorrent/alert_types.hpp
index c1e947757..ca69492d7 100644
--- a/include/libtorrent/alert_types.hpp
+++ b/include/libtorrent/alert_types.hpp
@@ -212,7 +212,8 @@ namespace libtorrent
 			outstanding_disk_buffer_limit_reached,
 			outstanding_request_limit_reached,
 			upload_limit_too_low,
-			download_limit_too_low
+			download_limit_too_low,
+			send_buffer_watermark_too_low
 		};
 
 		performance_alert(torrent_handle const& h
@@ -232,7 +233,8 @@ namespace libtorrent
 				"max outstanding disk writes reached",
 				"max outstanding piece requests reached",
 				"upload limit too low (download rate will suffer)",
-				"download limit too low (upload rate will suffer)"
+				"download limit too low (upload rate will suffer)",
+				"send buffer watermark too low (upload rate will suffer)"
 			};
 
 			return torrent_alert::message() + ": performance warning: "
diff --git a/include/libtorrent/session_settings.hpp b/include/libtorrent/session_settings.hpp
index 3bc5fa360..4d923d263 100644
--- a/include/libtorrent/session_settings.hpp
+++ b/include/libtorrent/session_settings.hpp
@@ -119,7 +119,7 @@ namespace libtorrent
 #endif
 			, free_torrent_hashes(true)
 			, upnp_ignore_nonrouters(false)
- 			, send_buffer_watermark(80 * 1024)
+ 			, send_buffer_watermark(100 * 1024)
 			, auto_upload_slots(true)
 			, auto_upload_slots_rate_based(true)
 			, use_parole_mode(true)
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 9dab8b2d6..625e84853 100644
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -3658,7 +3658,14 @@ namespace libtorrent
 		int buffer_size_watermark = int(m_statistics.upload_rate()) / 2;
 		if (buffer_size_watermark < 512) buffer_size_watermark = 512;
 		else if (buffer_size_watermark > m_ses.settings().send_buffer_watermark)
+		{
 			buffer_size_watermark = m_ses.settings().send_buffer_watermark;
+			if (t->alerts().should_post<performance_alert>())
+			{
+				t->alerts().post_alert(performance_alert(t->get_handle()
+					, performance_alert::send_buffer_watermark_too_low));
+			}
+		}
 
 		while (!m_requests.empty()
 			&& (send_buffer_size() + m_reading_bytes < buffer_size_watermark))