On 11/16/2012 04:54 PM, Julien Desfossez wrote: > On 16/11/12 10:39 AM, Woegerer, Paul wrote: >> Does that mean that the live tracing feature that currently lives in the >> lttngtop-live branch will go into lttng-tools and babeltrace any time soon ? > > The main change of lttng-tools 2.2 is the live tracing feature. > The way it is implemented in the lttngtop-live branch is more a > proof-of-concept, we will be starting the clean implementation > discussions here as soon as we have lttng-tools 2.1 released (which > should be around the end of this month). > > In the mean time, to solve the problem you are currently experiencing, > you could manually add a flush on the metadata channel after the session > is started to make sure it is written on disk quickly (that's what is > done in lttngtop-live at the beginning). Of course like David said, if
I will try that. Thanks ! -- Paul > you have new events/applications enabled during tracing, the metadata > needs to be flushed again. > > Thanks, > > Julien > > >> >> Thanks >> Paul >> >>> >>> Thanks, >>> >>> Mathieu >>> >>>> >>>> Cheers! >>>> David >>>> >>>> Woegerer, Paul: >>>>> Hi, >>>>> >>>>> embedded users sometimes have to trace to tmpfs (e.g. streaming in not >>>>> an option due to missing network connectivity). >>>>> >>>>> Ramdisks of 16M to 128M size are created and as long as the ram disk >>>>> does not get full, tracing works fine. Unfortunately if the disk gets >>>>> full things fall apart: >>>>> >>>>> PERROR: Error in file write: No space left on device [in >>>>> lttng_consumer_on_read_subbuffer_mmap() at consumer.c:1367] >>>>> >>>>> The consumer daemon will not be able to write the metadata channel and >>>>> therefore the trace data set will be unusable (cannot be read with >>>>> babeltrace). >>>>> >>>>> -rwxrwxrwx 1 testuser users 0 Nov 16 11:22 metadata >>>>> -rwxrwxrwx 1 testuser users 15728640 Nov 16 11:22 myevents_0 >>>>> -rwxrwxrwx 1 testuser users 4096 Nov 16 11:22 myevents_1 >>>>> >>>>> Is it possible to somehow reserve the file size (fallocate) for metadata >>>>> so that in case the disk gets full at least the metadata gets written >>>>> and the resulting trace set is readable with babeltrace ? >>>>> >>>>> I wonder if that is possible at all. The consumer daemon doesn't know >>>>> upfront how much would need to be reserved for metadata, right ? >>>>> >>>>> Any ideas ? >>>>> >>>>> Thanks, >>>>> Paul >>>>> >>>>> >>>> >>>> _______________________________________________ >>>> lttng-dev mailing list >>>> [email protected] >>>> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev >>> >> >> -- Paul Woegerer | SW Development Engineer http://go.mentor.com/sourceryanalyzer Mentor Embedded(tm) | Prinz Eugen Straße 72/2/4, Vienna, 1040 Austria Nucleus® | Linux® | Android(tm) | Services | UI | Multi-OS Android is a trademark of Google Inc. Use of this trademark is subject to Google Permissions. Linux is the registered trademark of Linus Torvalds in the U.S. and other countries. _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
