From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Delivered-To: caml-list@yquem.inria.fr Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by yquem.inria.fr (Postfix) with ESMTP id 27797BCAE for ; Fri, 24 Jun 2005 18:39:30 +0200 (CEST) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by concorde.inria.fr (8.13.0/8.13.0) with ESMTP id j5OGdTMU017717 for ; Fri, 24 Jun 2005 18:39:29 +0200 Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id SAA23149 for ; Fri, 24 Jun 2005 18:39:29 +0200 (MET DST) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.196]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id j5OGdS9q024666 for ; Fri, 24 Jun 2005 18:39:28 +0200 Received: by wproxy.gmail.com with SMTP id 68so459812wra for ; Fri, 24 Jun 2005 09:39:25 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:mime-version:content-type; b=JnrXXp/J37j2Lw6BD8HZbdsXXeNZWYDBWM/PytrjhgYH2uBhrPamIXuIH854DWPCgq9qBCah/CVlmtak8SyCfptfpSnNhN0kUDEFw7lCnunpc3A1maz/Id0BRZc+odRU37lfNa0u+qMNOQbOcv+MC3Vnx2yHWitaa9bGMrN+LRk= Received: by 10.54.6.13 with SMTP id 13mr1785756wrf; Fri, 24 Jun 2005 09:39:24 -0700 (PDT) Received: by 10.54.2.21 with HTTP; Fri, 24 Jun 2005 09:39:24 -0700 (PDT) Message-ID: <891bd339050624093978a3c9a8@mail.gmail.com> Date: Fri, 24 Jun 2005 12:39:24 -0400 From: Yaron Minsky Reply-To: yminsky@cs.cornell.edu To: Caml Mailing List Subject: Why are backtraces (sometimes) useless Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_3701_19865421.1119631164777" X-Miltered: at concorde with ID 42BC3741.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Miltered: at nez-perce with ID 42BC3740.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; yaron:01 minsky:01 yminsky:01 ocaml:01 threads:01 stack:01 surprising:01 native-code:01 backtrace:01 ocaml:01 threads:01 stack:01 surprising:01 native-code:01 backtrace:01 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on yquem.inria.fr X-Spam-Status: No, score=0.2 required=5.0 tests=HTML_00_10,HTML_MESSAGE, RCVD_BY_IP autolearn=disabled version=3.0.2 X-Spam-Level: ------=_Part_3701_19865421.1119631164777 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline I've had a lot of experience lately with OCaml backtraces sucking, and I'm= =20 not sure what's going on. We're working on a decent-sizes project (about=20 10-kloc) that uses threads and a decent amount of functorization. One thing= =20 we've noticed is that backtraces are almost completely useless --- generall= y=20 speaking, they have lots of "Called from unknown location" messages, and=20 almost no useful data. They often skip over functions on the call stack of= =20 the error in surprising ways. I guess the question is this: what kind of situations cause backtraces to= =20 drop information in the ways described above? Also, is there anyone out there actively using the native-code backtrace=20 patches that people have come up with? I'm curious to hear other people's= =20 experiences. y ------=_Part_3701_19865421.1119631164777 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline I've had a lot of experience lately with OCaml backtraces sucking, and I'm not sure what's going on.  We're working on a decent-sizes project (about 10-kloc) that uses threads and a decent amount of functorization.  One thing we've noticed is that backtraces are almost completely useless --- generally speaking, they have lots of "Called from unknown location" messages, and almost no useful data.  They often skip over functions on the call stack of the error in surprising ways.

I guess the question is this:  what kind of situations cause backtrace= s to drop information in the ways described above?

Also, is there anyone out there actively using the native-code backtrace patches that people have come up with?  I'm curious to hear other people's experiences.

y

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