From mboxrd@z Thu Jan 1 00:00:00 1970 From: milian.wolff@kdab.com (Milian Wolff) Date: Fri, 27 Mar 2020 18:18:09 +0100 Subject: [lttng-dev] LTTng user-space callstacks In-Reply-To: <570185028.14544.1585317308324.JavaMail.zimbra@efficios.com> References: <570185028.14544.1585317308324.JavaMail.zimbra@efficios.com> Message-ID: <2063300.72vocr9iq0@agathebauer> On Freitag, 27. M?rz 2020 14:55:08 CET Mathieu Desnoyers wrote: > Last time I checked, the main issue with perf's handling of cases that lack > frame pointers is that they grab a ~2-4kB worth of stack data into the > trace, and then post-process it with libunwind. This might be OK for > sampling use-cases, but is not something I consider appropriate for tracing > due to considerably increased use of tracing throughput. > > Has the situation changed on the perf side ? Perf still does this. But heaptrack, of which I'm the main author, uses libunwind to unwind on every heap allocation and it's plenty fast. Obviously the impact is measureable and it's far away from even close to zero overhead. But it's super useful. I guess having that capability in LTTng would be similarly useful and if it's documented to have an overhead people can use it with care. Cheers -- Milian Wolff | milian.wolff at kdab.com | Senior Software Engineer KDAB (Deutschland) GmbH, a KDAB Group company Tel: +49-30-521325470 KDAB - The Qt, C++ and OpenGL Experts -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/pkcs7-signature Size: 3826 bytes Desc: not available URL: