Dr.-Ing. Christoph Cullmann via llvm-dev
2017-Jun-05 14:43 UTC
[llvm-dev] Question about llvm::Value::print performance
Dear Thomas,> Hi Christoph, > > maybe there is a way of caching the print outputs and output them at the > end of the program execution? > So, your real application do not have this kind of bottle neck.this is a valid idea, thought the problem is: I output all things only "once" and I even output it like: 1) load module 2) go over functions 3) output all blocks with instructions in the current function That allows to e.g. use ModuleSlotTracker to compute the <label> comments of blocks fast, as each function is only visited once. Still, the performance drop to just print each instruction once is "large", without instruction printing my control flow graph construction works in ~1 second, with printing I aborted after some minutes the execution. (the module is really large, linked full graph of some medium sized application, around 5000 functions and 500k instructions and a lot of debug/type info) If there is some way that I precompute things on my own, I would really like to use that, but I don't see a way to do that. Greetings Christoph> > Best regards, > Thomas > > Am 05.06.2017 16:30 schrieb Dr.-Ing. Christoph Cullmann via llvm-dev: >> Hi, >> >> I want to use llvm::Value::print to output the assembly strings for >> llvm::Instructions >> inside a rather large llvm::Module (linked module with lots of >> types/...). >> >> I started with plain ::print and switched over to >> >> http://llvm.org/docs/doxygen/html/classllvm_1_1Value.html#a04e6fc765eeb0c4c90ac5d55113db116 >> >> with a ModuleSlotTracker I pass in myself to avoid some complexity. >> >> Still now I have the issue that the TypeFinder::run and related that >> is done internally >> by each print still is 99% of my program runtime. (at least perf tells >> me that) >> >> Is there any clever workaround for this? >> >> I looked a bit through the sources but it seems that no API is >> exported that would allow a faster print >> call. >> >> Given I want the output only more or less as "debugging" annotation to >> my graph, is there some other >> "fast" way to print instructions, even if some info is missing then? >> >> Greetings >> Christoph > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev-- ----------------------------- Dr.-Ing. Christoph Cullmann --------- AbsInt Angewandte Informatik GmbH Email: cullmann at AbsInt.com Science Park 1 Tel: +49-681-38360-22 66123 Saarbrücken Fax: +49-681-38360-20 GERMANY WWW: http://www.AbsInt.com -------------------------------------------------------------------- Geschäftsführung: Dr.-Ing. Christian Ferdinand Eingetragen im Handelsregister des Amtsgerichts Saarbrücken, HRB 11234
Thomas Krüger via llvm-dev
2017-Jun-05 14:50 UTC
[llvm-dev] Question about llvm::Value::print performance
Hi Christoph, is it possible to reduce the amount of "work" for every process and iterate over all functions in different processes? I mean: Debug the first 100 functions, then in the socond step, debug function 101 till 200, and so on. So you summarize and complete your result over several, standalone debugs steps. Best regards, Thomas Am 05.06.2017 16:43 schrieb Dr.-Ing. Christoph Cullmann via llvm-dev:> Dear Thomas, > >> Hi Christoph, >> >> maybe there is a way of caching the print outputs and output them at >> the >> end of the program execution? >> So, your real application do not have this kind of bottle neck. > this is a valid idea, thought the problem is: I output all things only > "once" and I even > output it like: > > 1) load module > 2) go over functions > 3) output all blocks with instructions in the current function > > That allows to e.g. use ModuleSlotTracker to compute the <label> > comments of blocks fast, > as each function is only visited once. > > Still, the performance drop to just print each instruction once is > "large", without instruction printing > my control flow graph construction works in ~1 second, with printing I > aborted after some minutes the execution. > > (the module is really large, linked full graph of some medium sized > application, around 5000 functions and 500k instructions > and a lot of debug/type info) > > If there is some way that I precompute things on my own, I would > really like to use that, but I don't see a way > to do that. > > Greetings > Christoph > >> >> Best regards, >> Thomas >> >> Am 05.06.2017 16:30 schrieb Dr.-Ing. Christoph Cullmann via llvm-dev: >>> Hi, >>> >>> I want to use llvm::Value::print to output the assembly strings for >>> llvm::Instructions >>> inside a rather large llvm::Module (linked module with lots of >>> types/...). >>> >>> I started with plain ::print and switched over to >>> >>> http://llvm.org/docs/doxygen/html/classllvm_1_1Value.html#a04e6fc765eeb0c4c90ac5d55113db116 >>> >>> with a ModuleSlotTracker I pass in myself to avoid some complexity. >>> >>> Still now I have the issue that the TypeFinder::run and related that >>> is done internally >>> by each print still is 99% of my program runtime. (at least perf >>> tells >>> me that) >>> >>> Is there any clever workaround for this? >>> >>> I looked a bit through the sources but it seems that no API is >>> exported that would allow a faster print >>> call. >>> >>> Given I want the output only more or less as "debugging" annotation >>> to >>> my graph, is there some other >>> "fast" way to print instructions, even if some info is missing then? >>> >>> Greetings >>> Christoph >> _______________________________________________ >> LLVM Developers mailing list >> llvm-dev at lists.llvm.org >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
Dr.-Ing. Christoph Cullmann via llvm-dev
2017-Jun-05 14:55 UTC
[llvm-dev] Question about llvm::Value::print performance
Hi,> Hi Christoph, > > is it possible to reduce the amount of "work" for every process and > iterate over all functions in different processes? > I mean: Debug the first 100 functions, then in the socond step, debug > function 101 till 200, and so on. So you summarize and complete your > result over several, standalone debugs steps.not really, I need the graph with instruction labels in one go, as it will be used to visualize things, e.g. like this example that works on PPC assembly. (a bit like writing a dot graph of the IR) https://www.absint.com/stackanalyzer/shot5.png Beside, as the printing seems really like "per instruction redo all type importing and co." it won't even scale if I let all cores do things. The AssemblyWriter that is internal has rather clever caching for that which I can't access from the outside, if I am not wrong. But perhaps somebody has a clever way around this issue. Greetings Christoph> > Best regards, > Thomas > > Am 05.06.2017 16:43 schrieb Dr.-Ing. Christoph Cullmann via llvm-dev: >> Dear Thomas, >> >>> Hi Christoph, >>> >>> maybe there is a way of caching the print outputs and output them at >>> the >>> end of the program execution? >>> So, your real application do not have this kind of bottle neck. >> this is a valid idea, thought the problem is: I output all things only >> "once" and I even >> output it like: >> >> 1) load module >> 2) go over functions >> 3) output all blocks with instructions in the current function >> >> That allows to e.g. use ModuleSlotTracker to compute the <label> >> comments of blocks fast, >> as each function is only visited once. >> >> Still, the performance drop to just print each instruction once is >> "large", without instruction printing >> my control flow graph construction works in ~1 second, with printing I >> aborted after some minutes the execution. >> >> (the module is really large, linked full graph of some medium sized >> application, around 5000 functions and 500k instructions >> and a lot of debug/type info) >> >> If there is some way that I precompute things on my own, I would >> really like to use that, but I don't see a way >> to do that. >> >> Greetings >> Christoph >> >>> >>> Best regards, >>> Thomas >>> >>> Am 05.06.2017 16:30 schrieb Dr.-Ing. Christoph Cullmann via llvm-dev: >>>> Hi, >>>> >>>> I want to use llvm::Value::print to output the assembly strings for >>>> llvm::Instructions >>>> inside a rather large llvm::Module (linked module with lots of >>>> types/...). >>>> >>>> I started with plain ::print and switched over to >>>> >>>> http://llvm.org/docs/doxygen/html/classllvm_1_1Value.html#a04e6fc765eeb0c4c90ac5d55113db116 >>>> >>>> with a ModuleSlotTracker I pass in myself to avoid some complexity. >>>> >>>> Still now I have the issue that the TypeFinder::run and related that >>>> is done internally >>>> by each print still is 99% of my program runtime. (at least perf >>>> tells >>>> me that) >>>> >>>> Is there any clever workaround for this? >>>> >>>> I looked a bit through the sources but it seems that no API is >>>> exported that would allow a faster print >>>> call. >>>> >>>> Given I want the output only more or less as "debugging" annotation >>>> to >>>> my graph, is there some other >>>> "fast" way to print instructions, even if some info is missing then? >>>> >>>> Greetings >>>> Christoph >>> _______________________________________________ >>> LLVM Developers mailing list >>> llvm-dev at lists.llvm.org >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev-- ----------------------------- Dr.-Ing. Christoph Cullmann --------- AbsInt Angewandte Informatik GmbH Email: cullmann at AbsInt.com Science Park 1 Tel: +49-681-38360-22 66123 Saarbrücken Fax: +49-681-38360-20 GERMANY WWW: http://www.AbsInt.com -------------------------------------------------------------------- Geschäftsführung: Dr.-Ing. Christian Ferdinand Eingetragen im Handelsregister des Amtsgerichts Saarbrücken, HRB 11234