In this article, we will explore the GNU profiling tool ‘gprof’. In this step, the gprof tool is run with the executable name and the above. What is gprof? Gprof is a profiling program which collects and arranges statistics on your programs. Write hate-mail to gnu (but don’t tell them I told you to). Table of Contents. 1. Introduction to Profiling · 2. Compiling a Program for Profiling · 3. Executing the Program · 4. gprof Command Summary · Output Options.
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Anyway, as for why it would hang, a question and a suggestion on figuring out where its having issues: Read more about Ramesh Natarajan and the blog.
I have been using gprof to isolate a performance issue in a large scale business application, but recent attempts to do this have stalled. Note that I have used and will be using -b option so as to avoid extra information in analysis output. There is also an estimate of how much time was spent in the subroutines gpdof each gbu.
The main thing I was getting at is gprof has its uses and to dismiss it entirely is not always helpful but then so would be dismissing your points — they are valid. Unlike prof, gprof is capable of limited call graph collecting and printing.
Kiranjp September 3,1: Alex, The reason ctrl-c prevents it from producing a gmon. The amount of error is usually more than one sampling period. Hopefully that clears up any points from my end you did indeed clear up your points and I — besides being surprised you responded to me responding from your response from — appreciate it.
The human eye can recognize similarities between state samples stack and data that no summarizing backend of any profiler has any hope of exposing to the user. One final note gni that it is almost always not a system library g;rof when you see something hanging or crashing in a gpfof library e.
A call to the monitor function ‘mcount’ is inserted before each function call. That samples have to be taken at high frequency they do not. All rights reserved Terms of Service.
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This produces an analysis file which contains all the gprod profiling information. The second part of the output is the textual call graph, which shows for each function who called it parent and who it called child subroutines. Lets have a look at this text file:. This file contains a couple of tables flat profile and call graph in addition to some other information. If a value is n gpgof the sampling period, the expected error in the value is the square gpgof of n sampling periods.
Well, I ran the proram again, and this time it produced the gmon. But because difference in loops is small, every time program executes we can get different gu results in flat profile. If there are some static functions whose profiling information you do not require then this can be achieved using -a option:. That self time matters as opposed to inclusive time, which includes self time.
Well your points are also valid. Could you please add details about how to get gmon. Oh no, the world is NOT perfect and only a fool would think otherwise or think that only perfection is valuable.
Support Us Support this blog by purchasing glrof of my ebooks. It produced the gmon. It used a hybrid of instrumentation and sampling  and was created as an extended version of the older “prof” tool. That invocation counting is useful as opposed to getting inclusive time percent. Hi Is it possible to set the gmon. Hi Mike, Well your points are also valid. Gmu is sorted by percentage, with hot spots at the top of the list.
As you would have already seen that gprof produces output with lot of verbose information so in case this information is not required then this can be achieved using the -b flag. Rewording 3rd from last paragraph: The mcount function may not be thread-safe in some gnk, so multi-threaded application profiles can be incorrect typically it only profiles the main thread of application. Now lets see the analysis output:.
Do you have any idea why? You can also simply drop me a line to say hello!.