X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=2.9%2Flttng-docs-2.9.txt;fp=2.9%2Flttng-docs-2.9.txt;h=53d575f2d1edad7c5eedf1251defe4ac67b7a281;hb=3cd5f5046bca14706abaa8362af9741f9a86128f;hp=dcff639d5d9fa1a6d224333b75efbeb2c810913f;hpb=489967cfd5d44bf6a386f672e5093c949470491c;p=lttng-docs.git diff --git a/2.9/lttng-docs-2.9.txt b/2.9/lttng-docs-2.9.txt index dcff639..53d575f 100644 --- a/2.9/lttng-docs-2.9.txt +++ b/2.9/lttng-docs-2.9.txt @@ -1,7 +1,7 @@ The LTTng Documentation ======================= Philippe Proulx -v2.9, 22 January 2018 +v2.9, 25 February 2021 include::../common/copyright.txt[] @@ -1033,11 +1033,11 @@ LTTng can send the generated trace data to different locations. The _tracing session mode_ dictates where to send it. The following modes are available in LTTng{nbsp}{revision}: -Local mode:: +[[local-mode]]Local mode:: LTTng writes the traces to the file system of the machine being traced (target system). -Network streaming mode:: +[[net-streaming-mode]]Network streaming mode:: LTTng sends the traces over the network to a <> running on a remote system. @@ -1048,7 +1048,7 @@ Snapshot mode:: or to send it over the network to a <> running on a remote system. -Live mode:: +[[live-mode]]Live mode:: This mode is similar to the network streaming mode, but a live trace viewer can connect to the distant relay daemon to <> by @@ -1204,13 +1204,18 @@ discard mode, the tracer only discards the event record that doesn't fit. In discard mode, LTTng increments a count of lost event records when an -event record is lost and saves this count to the trace. In overwrite -mode, since LTTng 2.8, LTTng increments a count of lost sub-buffers when -a sub-buffer is lost and saves this count to the trace. In this mode, -the exact number of lost event records in those lost sub-buffers is not -saved to the trace. Trace analyses can use the trace's saved discarded -event record and sub-buffer counts to decide whether or not to perform -the analyses even if trace data is known to be missing. +event record is lost and saves this count to the trace. Since +LTTng{nbsp}2.8, in overwrite mode, LTTng writes to a given sub-buffer +its sequence number within its data stream. With a <>, +<>, or <> +<>, a trace reader can use such +sequence numbers to report lost packets. In overwrite mode, LTTng +doesn't write to the trace the exact number of lost event records in +those lost sub-buffers. + +Trace analyses can use saved discarded event record and sub-buffer +(packet) counts of the trace to decide whether or not to perform the +analyses even if trace data is known to be missing. There are a few ways to decrease your probability of losing event records.