Ah, that clears it up. Thank you Simon. -Brian
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Simon Marchi Sent: Thursday, October 22, 2015 6:50 PM To: Brian Robbins <[email protected]> Cc: lttng-dev <[email protected]> Subject: Re: [lttng-dev] Ubuntu Package for LTTng-UST Compiled with Debug Logging On By Default On 22 October 2015 at 19:35, Brian Robbins <[email protected]> wrote: > Hello, > > > > The Linux build of CoreCLR now supports tracing using LTTng-UST. One > artifact that we noticed when running on Ubuntu 14.04 in our CI is > that apps running on CoreCLR all have an LTTng warning written to stderr: > > > > libust[883/883]: Warning: HOME environment variable not set. Disabling > LTTng-UST per-user tracing. (in setup_local_apps() at > lttng-ust-comm.c:305) > > > > I’ve investigated, and it is true that in the CI, there is no HOME > environment variable. However, what I’m more interested in is why > this message is written in the first place. Looking in at the latest > LTTng-UST code, it appears that this message should only be logged > when debug logging is enabled. From code inspection, it appears that > debug logging can be enabled at either compile time (#define > LTTNG_UST_DEBUG) or at runtime via an environment variable called > LTTNG_UST_DEBUG. > > > > I have confirmed that the environment variable LTTNG_UST_DEBUG is not > present. I’ve also looked at the disassembly, and can confirm that > the ust_loglevel check is not actually performed (the if statement is > optimized away). This makes me think that the Ubuntu package was > compiled with LTTNG_UST_DEBUG defined. > > > > The package in question is old – LTTng-UST 2.4. I’m wondering if > either debug logging was always present in 2.4, or if the package was > compiled with LTTNG_UST_DEBUG. I would expect that most customers > would want debug logging off by default, since it affects the output of the > program. > > > > Your help in figuring this out is greatly appreciated. > > > > Thank you. > > -Brian Hi Brian, This warning used to appear regardless of the definition of LTTNG_UST_DEBUG. Bisecting shows that it has been fixed in commit 7bdd21a41092a59207958911666cbd458f93a319, which is part of version 2.7. Here it is: https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2fgit.lttng.org%2f%3fp%3dlttng-ust.git%3ba%3dcommit%3bh%3d7bdd21a41092a59207958911666cbd458f93a319&data=01%7c01%7cbrianrob%40microsoft.com%7c99b5a8acab4a4f5011fb08d2db4c43b3%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=zTME%2f%2bZcLfwBF8%2bSfSKgC8wo1I14REelMFZlkUYWByA%3d Simon _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
