Revision: 3677
Author: mikhail.naganov
Date: Thu Jan 21 14:52:00 2010
Log: Edited wiki page through web user interface.
http://code.google.com/p/v8/source/detail?r=3677
Modified:
/wiki/V8Profiler.wiki
=======================================
--- /wiki/V8Profiler.wiki Tue Jul 14 11:31:31 2009
+++ /wiki/V8Profiler.wiki Thu Jan 21 14:52:00 2010
@@ -49,6 +49,20 @@
{{{
tools/mac-tick-processor v8.log
}}}
+
+== Snapshot-based VM build and builtins reporting ==
+
+When a snapshot-based VM build is being used, code objects from a snapshot
that doesn't correspond to function objects are reported with generic names
like _"A builtin from the snapshot"_, because their real names are not
stored in the snapshot. To see the names the following steps must be taken:
+
+ * `--log-snapshot-positions` flag must be passed to VM (along with
`--prof`); this way, for deserialized objects the `(memory address,
snapshot offset)` pairs are being emitted into profiler log;
+
+ * `--snapshot-log=<log file from mksnapshot>` flag must be passed to the
tick processor script; a log file from the `mksnapshot` program (a snapshot
log) contains address-offset pairs for serialized objects, and their names;
using the snapshot log, names can be mapped onto deserialized objects
during profiler log processing; the snapshot log file is called
`snapshot.log` and resides alongside with V8's compiled files.
+
+An example of usage:
+{{{
+./shell --prof --log-snapshot-positions script.js
+tools/linux-tick-processor --snapshot-log=obj/release/snapshot.log v8.log
+}}}
= Programmatic Control of Profiling =
If you would like to control in your application when profile samples are
collected, you can do so.
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