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From: Yeshurun, M. <mei...@in...> - 2006-03-29 14:19:34
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Thanks, I understand. However, the "I'm not reporting anymore" message usually appears when the exact same error is executed many times (e.g. an error that happens to be inside a loop). According to your reply, using --error-limit=3Dno = in this case shouldn't be a problem. It should only be a problem when you're getting a huge log file with many different call stacks. Did I understand correctly? Thanks, Meir -----Original Message----- From: val...@li... [mailto:val...@li...] On Behalf Of Julian Seward Sent: Wednesday, March 29, 2006 3:51 PM To: val...@li... Cc: Yeshurun, Meir Subject: Re: [Valgrind-users] Effect of --error-limit=3Dno on = performance > Can using --error-limit=3Dno (instead of suppressions) cause a significant > performance degradation, and if so, how much? Yes -- that's why the limit exists in the first place. As you know V only displays each error the first time it appears, and so if your program has huge numbers of errors it can spend a lot of time=20 checking incoming errors to find out if it has seen them before already. Note, the cost of this search is proportional to the number of different error call-stacks involved. So if the same error is seen one million times that's no big deal, but if you have one million different errors each of which have only happened once then the cost of checking a=20 new error will be huge. Does that make sense? J ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=3D110944&bid=3D241720&dat=3D= 121642 _______________________________________________ Valgrind-users mailing list Val...@li... https://lists.sourceforge.net/lists/listinfo/valgrind-users |
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From: Nicholas N. <nj...@cs...> - 2006-03-29 21:56:03
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On Wed, 29 Mar 2006, Yeshurun, Meir wrote: > However, the "I'm not reporting anymore" message usually appears when > the exact same error is executed many times (e.g. an error that happens > to be inside a loop). According to your reply, using --error-limit=no in > this case shouldn't be a problem. It should only be a problem when > you're getting a huge log file with many different call stacks. Did I > understand correctly? That sounds right. As the manual says: When enabled, Valgrind stops reporting errors after 100000 in total, or 1000 different ones, have been seen. This is to stop the error tracking machinery from becoming a huge performance overhead in programs with many errors. Maybe the 100000 total limit isn't important and could be dropped, for the reasons discussed above. Nick |