From 3cd5f5046bca14706abaa8362af9741f9a86128f Mon Sep 17 00:00:00 2001 From: Philippe Proulx Date: Thu, 25 Feb 2021 13:13:00 -0500 Subject: [PATCH] 2.8-2.12: "lost packets" is only meaningful for non-snapshot modes With a snapshot mode tracing session, the channels are in "overwrite" mode automatically: the tracers continuously overwrite the oldest sub-buffers, incrementing their sequence numbers meanwhile. The overwritten sub-buffers between two snapshots are not lost packets in this case: they were not meant to be recorded in the first place. Fix `lttng-docs-2.8.txt` to `lttng-docs-2.12.txt` to clarify this, with new internal links to tracing session mode descriptions. Signed-off-by: Philippe Proulx --- 2.10/lttng-docs-2.10.txt | 27 ++++++++++++++++----------- 2.11/lttng-docs-2.11.txt | 27 ++++++++++++++++----------- 2.12/lttng-docs-2.12.txt | 26 +++++++++++++++----------- 2.8/lttng-docs-2.8.txt | 27 ++++++++++++++++----------- 2.9/lttng-docs-2.9.txt | 27 ++++++++++++++++----------- 5 files changed, 79 insertions(+), 55 deletions(-) diff --git a/2.10/lttng-docs-2.10.txt b/2.10/lttng-docs-2.10.txt index 2a5c2f4..375fcf5 100644 --- a/2.10/lttng-docs-2.10.txt +++ b/2.10/lttng-docs-2.10.txt @@ -1,7 +1,7 @@ The LTTng Documentation ======================= Philippe Proulx -v2.10, 18 October 2019 +v2.10, 25 February 2021 include::../common/copyright.txt[] @@ -1022,11 +1022,11 @@ 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. @@ -1037,7 +1037,7 @@ 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 @@ -1202,13 +1202,18 @@ 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. diff --git a/2.11/lttng-docs-2.11.txt b/2.11/lttng-docs-2.11.txt index ea3f409..9d5d083 100644 --- a/2.11/lttng-docs-2.11.txt +++ b/2.11/lttng-docs-2.11.txt @@ -1,7 +1,7 @@ The LTTng Documentation ======================= Philippe Proulx -v2.11, 5 August 2020 +v2.11, 25 February 2021 include::../common/copyright.txt[] @@ -1303,11 +1303,11 @@ 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 it traces (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. @@ -1318,7 +1318,7 @@ Snapshot mode:: target's file system 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 <>. @@ -1476,13 +1476,18 @@ 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{nbsp}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, LTTng does not write to the trace the exact number of lost event -records in those lost sub-buffers. 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. diff --git a/2.12/lttng-docs-2.12.txt b/2.12/lttng-docs-2.12.txt index d80ba30..4b87947 100644 --- a/2.12/lttng-docs-2.12.txt +++ b/2.12/lttng-docs-2.12.txt @@ -1441,11 +1441,11 @@ 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 it traces (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. @@ -1457,7 +1457,7 @@ that is, a copy of the current sub-buffers of the tracing session, and to write it to the file system of the target 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 <>. @@ -1615,14 +1615,18 @@ 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{nbsp}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, 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 counts of the trace 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. diff --git a/2.8/lttng-docs-2.8.txt b/2.8/lttng-docs-2.8.txt index f8f6d92..9ccf4ca 100644 --- a/2.8/lttng-docs-2.8.txt +++ b/2.8/lttng-docs-2.8.txt @@ -1,7 +1,7 @@ The LTTng Documentation ======================= Philippe Proulx -v2.8, 24 July 2017 +v2.8, 25 February 2021 include::../common/copyright.txt[] @@ -1074,11 +1074,11 @@ 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. @@ -1089,7 +1089,7 @@ 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 @@ -1245,13 +1245,18 @@ 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. 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. -- 2.34.1