search for: instrument

Displaying 20 results from an estimated 2584 matches for "instrument".

2015 Aug 08
2
RFC: PGO Late instrumentation for LLVM
Accidentally sent to uiuc server. On Fri, Aug 7, 2015 at 10:49 PM, Sean Silva <chisophugis at gmail.com> wrote: > Can you compare your results with another approach: simply do not > instrument the top 1% hottest functions (by function entry count)? If this > simple approach provides most of the benefits (my measurements on one > codebase I tested show that it would eliminate over 97% of total function > counts), we may be able to use a simpler approach. > > The biggest thi...
2015 Aug 10
3
RFC: PGO Late instrumentation for LLVM
...ugis at gmail.com> wrote: > > Accidentally sent to uiuc server. > > > > > > On Fri, Aug 7, 2015 at 10:49 PM, Sean Silva <chisophugis at gmail.com> > wrote: > >> > >> Can you compare your results with another approach: simply do not > >> instrument the top 1% hottest functions (by function entry count)? If > this > >> simple approach provides most of the benefits (my measurements on one > >> codebase I tested show that it would eliminate over 97% of total > function > >> counts), we may be able to use a simple...
2015 Aug 08
3
RFC: PGO Late instrumentation for LLVM
Instrumentation based Profile Guided Optimization (PGO) is a compiler technique that leverages important program runtime information, such as precise edge counts and frequent value information, to make frequently executed code run faster. It's proven to be one of the most effective ways to improve program...
2019 Jan 21
2
[X-ray] How to check successful instrumentation and generate call trace?
Hi all, I want to test X-ray performance and compare it with other research tools, so I use Clang 7.0.0 to compile and instrument GNU binutils-2.3.1 with the following commands: cd binutils-2.31/ mkdir build cd build/ CC=$local/clang CXX=$local/clang++ CFLAGS=-fxray-instrument CXXFLAGS=-fxray-instrument ../configure --prefix=/home/zhangysh1995/local make Then I extract instrumentation map...
2011 Nov 14
2
[LLVMdev] Re moving the instrumented instructions at runtime
Hello, I have some questions about removing the instrumented instructions at runtime. Assume I instrument some instructions by using some transformation passes. At runtime, I just need those instrumented instructions at the beginning, and I would like to remove instrumented instructions at runtime to reduce overhead. Does anyone know how to do this by...
2016 Jun 16
10
RFC: Comprehensive Static Instrumentation
Hey LLVM-dev, We propose to build the CSI framework to provide a comprehensive suite of compiler-inserted instrumentation hooks that dynamic-analysis tools can use to observe and investigate program runtime behavior. Traditionally, tools based on compiler instrumentation would each separately modify the compiler to insert their own instrumentation. In contrast, CSI inserts a standard collection of instrumentati...
2016 Jun 16
2
RFC: Comprehensive Static Instrumentation
...PM, Mehdi Amini <mehdi.amini at apple.com> wrote: > > On Jun 16, 2016, at 9:01 AM, TB Schardl via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > > Hey LLVM-dev, > > We propose to build the CSI framework to provide a comprehensive suite of > compiler-inserted instrumentation hooks that dynamic-analysis tools can use > to observe and investigate program runtime behavior. Traditionally, tools > based on compiler instrumentation would each separately modify the compiler > to insert their own instrumentation. In contrast, CSI inserts a standard > collect...
2013 Feb 24
2
[LLVMdev] How to measure the overhead of instrumented code
Hello all, I have developed a instrumented pass which insert some variables between the original variables, as well as insert some code into the original source code. just like: ============= original source code ============= int a[10]; void fun1 () { // some source code here } =========================================...
2011 Nov 14
0
[LLVMdev] Re moving the instrumented instructions at runtime
> Assume I instrument some instructions by using some transformation passes. > At runtime, I just need those instrumented instructions at the beginning, > and I would like to remove instrumented instructions at runtime to reduce > overhead. At the beginning of what? You mean at the time of program starup? T...
2004 Apr 07
5
[LLVMdev] Automating Diagnostic Instrumentation
Dear List, I have some questions about some passes for LLVM that I'm thinking about but first I need to give a little background ... One of the things I do in my "day job" (large IT system performance analysis) is to figure out where to place diagnostic instrumentation within an application. The instrumentation I'm talking about here is the kind that is inserted into application code to capture things like wall-clock latency, cpu time, number of i/o requests, etc. For accurate diagnosis, it is often necessary to collect that kind of data about ev...
2016 Jun 17
5
RFC: Comprehensive Static Instrumentation
....com> > wrote: > >> >> On Jun 16, 2016, at 9:01 AM, TB Schardl via llvm-dev < >> llvm-dev at lists.llvm.org> wrote: >> >> Hey LLVM-dev, >> >> We propose to build the CSI framework to provide a comprehensive suite of >> compiler-inserted instrumentation hooks that dynamic-analysis tools can use >> to observe and investigate program runtime behavior. Traditionally, tools >> based on compiler instrumentation would each separately modify the compiler >> to insert their own instrumentation. In contrast, CSI inserts a standard...
2016 Dec 19
1
Reining in profile instrumentation
Thanks Vedant, and my apologies for the delay getting back to you - work got "busy". I wasn't aware of the '-fprofile-generate' option, so thanks for point this out. I have tried running it and I can see the instrumentation hooks that it generates - I assume that there is a library I have to implement to support this, can you let me know where the source for this library is? This approach uses the C++ ctor initialisation support which is generally fine. However, in many cases in our embedded target programmers...
2016 Jun 16
4
RFC: Comprehensive Static Instrumentation
...> CC'ing the mailing list for the CSI project. > > On Thu, Jun 16, 2016 at 12:01 PM, TB Schardl <neboat at mit.edu> wrote: > >> Hey LLVM-dev, >> >> >> We propose to build the CSI framework to provide a comprehensive suite of >> compiler-inserted instrumentation hooks that dynamic-analysis tools can use >> to observe and investigate program runtime behavior. Traditionally, tools >> based on compiler instrumentation would each separately modify the compiler >> to insert their own instrumentation. In contrast, CSI inserts a standard...
2016 Mar 22
3
Instrumented BB in PGO
Hello, I have a question regarding PGO instrumented BBs (I use IR-level instrumentation). It seems that instrumented BBs do not match between the two compilations for profile-gen and profile-use for some cases. Here is an example from SPECcpu 2006 lbm (a simple case consisting of just two modules). In the first compilation, we have 5 instrumentat...
2004 Apr 07
0
[LLVMdev] Automating Diagnostic Instrumentation
Reid, Adding this kind of instrumentation pass would be very valuable in LLVM. We don't have any such thing at present, and there could be multiple uses for it. Joel Stanley did an MS thesis last year that could complement this kind of pass nicely. Joel's thesis was on dynamic performance instrumentation guided by expli...
2015 Aug 19
3
RFC: PGO Late instrumentation for LLVM
...have good knowledge of the code base. What we measure is running time for clang to compile a large preprocessed source file (4.98M lines of .ii file), using different compilation modes. All the numbers reported here are the average running time of 5 runs in seconds. *(1) Performance b/w late instrumentation v.s. not instrumenting single BB functions* We first compare various instrumentation performance. ---------------------------------------------------------------------------- Config wall_time_for_instr ratio_vs_base profile_size (1) base O2 80.386...
2014 May 29
4
[LLVMdev] Unifying TSan blacklist and no_sanitize_thread
Hi, I consider reducing the usage of blacklist in sanitizer instrumentation passes and doing the necessary work in frontend (Clang) instead. Some of it is already implemented: e.g. Clang will attach an attribute "sanitize_address" to function definition only if this function is not blacklisted. In this case we won't instrument the memory accesses in thi...
2016 Dec 13
0
Reining in profile instrumentation
> On Dec 13, 2016, at 3:46 AM, Martin J. O'Riordan via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > When either ‘-pg’ or ‘-finstrument-functions’ is used, the compiler inserts the appropriate profiling hooks. This happens prior to inlining, so the hooks remain in place. Have you tried compiling with -fprofile-generate? It enables IR-based profiling instrumentation, which has supported pre-inlining since r275588. That should miti...
2015 Aug 11
4
RFC: PGO Late instrumentation for LLVM
One aspect of this that I have not seen discussed is that middle-end instrumentation enables PGO optimizations to front-ends other than Clang. While I agree that FE instrumentation could be improved, it still requires every FE to implement essentially the same common functionality. Having PGO instrumentation generated in the middle-end, allows us every FE to automatically ta...
2015 Sep 01
3
RFC: PGO Late instrumentation for LLVM
...base. > > What we measure is running time for clang to compile a large preprocessed > source file (4.98M lines of .ii file), using different compilation modes. > All the numbers reported here are the average running time of 5 runs in > seconds. > > *(1) Performance b/w late instrumentation v.s. not instrumenting single BB > functions* > > We first compare various instrumentation performance. > > ---------------------------------------------------------------------------- > Config wall_time_for_instr ratio_vs_base > profile_size > (1)...