X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fring_buffer_vfs.c;h=71991ebb29554ba9b2df713a73750d6e79acc843;hb=7337bad8813e5d9ec7f37669afb3ec3bf07937da;hp=4389b5f6562ff9e03326cd1724f1b6086123ae79;hpb=b6155a916c35bfa4c4e5d49c52072e12c3daebba;p=lttng-modules.git

diff --git a/lib/ringbuffer/ring_buffer_vfs.c b/lib/ringbuffer/ring_buffer_vfs.c
index 4389b5f6..71991ebb 100644
--- a/lib/ringbuffer/ring_buffer_vfs.c
+++ b/lib/ringbuffer/ring_buffer_vfs.c
@@ -191,6 +191,15 @@ long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd,
 
 	switch (cmd) {
 	case RING_BUFFER_SNAPSHOT:
+		/*
+		 * First, ensure we perform a "final" flush onto the
+		 * stream.  This will ensure we create a packet of
+		 * padding if we encounter an empty packet. This ensures
+		 * the time-stamps right before the snapshot is used as
+		 * end of packet timestamp.
+		 */
+		if (!buf->quiescent)
+			lib_ring_buffer_switch_remote_empty(buf);
 		return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
 					    &buf->prod_snapshot);
 	case RING_BUFFER_SNAPSHOT_GET_CONSUMED:
@@ -320,6 +329,15 @@ long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
 
 	switch (cmd) {
 	case RING_BUFFER_COMPAT_SNAPSHOT:
+		/*
+		 * First, ensure we perform a "final" flush onto the
+		 * stream.  This will ensure we create a packet of
+		 * padding if we encounter an empty packet. This ensures
+		 * the time-stamps right before the snapshot is used as
+		 * end of packet timestamp.
+		 */
+		if (!buf->quiescent)
+			lib_ring_buffer_switch_remote_empty(buf);
 		return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
 						&buf->prod_snapshot);
 	case RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED: