<div><div dir="auto">Vans,</div><div dir="auto"><br></div><div dir="auto">Can you please share how to track these large binaries with let’s say Erlang 20 and/or HIPE?</div><div dir="auto"><br></div><div dir="auto">This will be useful to all of us and Devon can certainly downgrade to Erlang 20 to at least identify the culprit. </div><div dir="auto"><br></div><div dir="auto">/Frank</div></div><div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr"><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204,204,204)"><div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:13px"><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"></div>
<div dir="ltr" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">This used to be possible via the instrument module but the functionality got removed in OTP21, I used this functionality to detect a large binheap leak in jiffy way back when. Theres a lengthy discussion here under a PR called "improve instrumentation" but it really just "removed instrumentation" <span style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><a href="https://github.com/erlang/otp/pull/1790" rel="nofollow" target="_blank" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">https://github.com/erlang/otp/pull/1790</a>.<br></span><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br></div><div dir="ltr" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">There are BIF debug functions under hipe that can print this information. hipe_bifs:show_heap/1 and friends.</div></div>
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On Wednesday, April 8, 2020, 02:53:49 p.m. EDT, Dániel Szoboszlay <<a href="mailto:dszoboszlay@gmail.com" target="_blank" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">dszoboszlay@gmail.com</a>> wrote:
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<div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><div id="m_-4622445273957406379yiv5226392344" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><div dir="ltr" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Hi,<div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Even though you cannot trace on allocating large binaries, you may try tracing garbage collections, and look for GC-s that clean up a lot of off-heap binary data. This could at least narrow done the search for some processes, although it won't tell you where the allocation happens. But maybe once you know which processes are guilty you will be able to add more targeted tracing until you find the root cause.</div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Cheers,</div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Daniel</div></div><br clear="none"><div id="m_-4622445273957406379yiv5226392344yqt83720" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><div dir="ltr" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">On Wed, 8 Apr 2020 at 16:14, Lukas Larsson <<a rel="nofollow" shape="rect" href="mailto:lukas@erlang.org" target="_blank" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">lukas@erlang.org</a>> wrote:<br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;border-left-color:rgb(204,204,204)"><div dir="ltr" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Hello,</div><br clear="none"><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><div dir="ltr" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">On Tue, Apr 7, 2020 at 9:26 AM Devon Estes <<a rel="nofollow" shape="rect" href="mailto:devon.c.estes@gmail.com" target="_blank" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">devon.c.estes@gmail.com</a>> wrote:<br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;border-left-color:rgb(204,204,204)"><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Hi all,</div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">I’m seeing some cases in my application where our off-process binary heap allocation jumps by several orders of magnitude and then goes down right after. I’m sure this is something that’s in our app just loading dozens of huge binaries into memory at once and not a bug in anything underlying or a binary leak, but finding where these allocations are happening so I can make some changes to avoid this has so far not yielded any results. Ideally I’d like to be able to set a trace with something like erlang:trace/3 on some function that sends a tracer message whenever a binary over 30MB is allocated and includes the call stack or even just the calling function that allocated the binary in the trace message. </div></blockquote><blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;border-left-color:rgb(204,204,204)"><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Going through the binary vheap and getting a list of the processes that have references to those binaries won’t help in this case.</div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Is such a trace possible? Is there some flag I can set when starting my BEAM process to give me some kind of debug output that would give me this information? I’d imagine this is all in C, so it might be a bit tricky...</div></blockquote><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">No it is not possible without modifying the VM. I can't think of any good way to get this information without scanning the process' vheap, which as you say would not help much in this case.</div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;border-left-color:rgb(204,204,204)"><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Thanks in advance for the help!</div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none"></div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Cheers,</div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">Devon</div>-- <br clear="none"><div dir="ltr" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><div dir="ltr" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif"><br clear="none">_________________<br clear="none">Devon Estes<br clear="none"><a rel="nofollow" shape="rect" href="http://203.559.0323" target="_blank" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">203.559.0323</a><br clear="none"><a rel="nofollow" shape="rect" href="http://www.devonestes.com" target="_blank" style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif">www.devonestes.com</a><br clear="none"><br clear="none"></div></div>
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