Gprof Bus Error
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challenged and removed. (July 2015) (Learn how and when to remove this template message) In computing, a bus error is a fault raised by hardware, notifying an operating system (OS) that
Bus Error In Linux
a process is trying to access memory that the CPU cannot physically bus error (core dumped) in linux address: an invalid address for the address bus, hence the name. In modern use on most architectures these are
How To Debug Bus Error
much rarer than segmentation faults, which occur primarily due to memory access violations: problems in the logical address or permissions. On POSIX-compliant platforms, bus errors usually result in the SIGBUS signal how to solve bus error in linux being sent to the process that caused the error. SIGBUS can also be caused by any general device fault that the computer detects, though a bus error rarely means that the computer hardware is physically broken—it is normally caused by a bug in a program's source code.[citation needed] Bus errors may also be raised for certain other paging errors; see below. Contents 1 bus error core dumped c programming Causes 1.1 Non-existent address 1.2 Unaligned access 1.3 Paging errors 2 Example 3 References Causes[edit] There are at least three main causes of bus errors: Non-existent address[edit] Software instructs the CPU to read or write a specific physical memory address. Accordingly, the CPU sets this physical address on its address bus and requests all other hardware connected to the CPU to respond with the results, if they answer for this specific address. If no other hardware responds, the CPU raises an exception, stating that the requested physical address is unrecognized by the whole computer system. Note that this only covers physical memory addresses. Trying to access an undefined virtual memory address is generally considered to be a segmentation fault rather than a bus error, though if the MMU is separate, the processor can't tell the difference. Unaligned access[edit] Most CPUs are byte-addressable, where each unique memory address refers to an 8-bit byte. Most CPUs can access individual bytes from each memory address, but they generally cannot access larger units (16 bits, 32 bits, 64 bits and so on) without these units being "aligned" to a
the `-pg' option when you run the compiler. (This is in addition to the options you normally use.) To link the program for profiling, if you use a compiler such as cc to do the linking, simply specify `-pg' in addition to your usual options. The
Sigbus Error Linux
same option, `-pg', alters either compilation or linking to do what is necessary for profiling. Here bus error vs segmentation fault are examples: cc -g -c myprog.c utils.c -pg cc -o myprog myprog.o utils.o -pg The `-pg' option also works with a command that both compiles
Bus Error 10 Mac
and links: cc -o myprog myprog.c utils.c -g -pg Note: The `-pg' option must be part of your compilation options as well as your link options. If it is not then no call-graph data will be gathered and when you https://en.wikipedia.org/wiki/Bus_error run gprof you will get an error message like this: gprof: gmon.out file is missing call-graph data If you add the `-Q' switch to suppress the printing of the call graph data you will still be able to see the time samples: Flat profile: Each sample counts as 0.01 seconds. % cumulative self self total time seconds seconds calls Ts/call Ts/call name 44.12 0.07 0.07 zazLoop 35.29 0.14 0.06 main 20.59 0.17 0.04 bazMillion If you run the linker ld directly https://sourceware.org/binutils/docs/gprof/Compiling.html instead of through a compiler such as cc, you may have to specify a profiling startup file gcrt0.o as the first input file instead of the usual startup file crt0.o. In addition, you would probably want to specify the profiling C library, libc_p.a, by writing `-lc_p' instead of the usual `-lc'. This is not absolutely necessary, but doing this gives you number-of-calls information for standard library functions such as read and open. For example: ld -o myprog /lib/gcrt0.o myprog.o utils.o -lc_p If you are running the program on a system which supports shared libraries you may run into problems with the profiling support code in a shared library being called before that library has been fully initialised. This is usually detected by the program encountering a segmentation fault as soon as it is run. The solution is to link against a static version of the library containing the profiling support code, which for gcc users can be done via the `-static' or `-static-libgcc' command line option. For example: gcc -g -pg -static-libgcc myprog.c utils.c -o myprog If you compile only some of the modules of the program with `-pg', you can still profile the program, but you won't get complete information about the modules that were compiled without `-pg'. The only information you get for the functions in those modules is the total time spent in them; there is no record of how many times they were called, or from where.
egcs at cygnus dot com Subject: gprof basic-block counting? https://gcc.gnu.org/ml/gcc/1998-08/msg00560.html From: "Fred Richardson (at home)"
your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. Welcome to Qt Centre. Qt Centre is a community site devoted to programming in C++ using the Qt framework. Over 90 percent of questions asked here gets answered. If you are looking for information about Qt related issue — register and post your question. You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today! If you have any problems with the registration process or your account login, please contact us. + Reply to Thread Results 1 to 1 of 1 Thread: gprof doesn't work Thread Tools Show Printable Version Subscribe to this Thread… Search Thread Advanced Search Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode 10th May 2012,14:49 #1 soul_rebel View Profile View Forum Posts View Blog Entries View Articles Intermediate user Join Date Jan 2006 Location germany Posts 75 Thanks 9 Qt products Platforms gprof doesn't work I want to profile my multi-threaded gui-app, so I added: Qt Code: Switch view QMAKE_CXXFLAGS_DEBUG += -pgQMAKE_LFLAGS_DEBUG += -pg QMAKE_CXXFLAGS_DEBUG += -pg QMAKE_LFLAGS_DEBUG += -pg To copy to clipboard, switch view to plain text mode to my project file. Everything gets built ok, but as soon as I start the program it sigbusses with: Qt Code: Switch view Program received signal SIGBUS, Bus error.[Switching to Thread 29c04600 (LWP 100853/kports)]0x2917fc29 in .got.plt () from /usr/local/lib/qt4/libQtCore.so.4(gdb) bt#0 0x2917fc29 in .got.plt () from /usr/local/lib/qt4/libQtCore.so.4#1 0x01b14c29 in ?? ()#2 0xc0ed1029 in ?? ()#3 0xbfd97029 in ?? ()#4 0xc1a0c0bf in ?? () Program received signal SIGBUS, Bus error. [Switching to Thread 29c04600 (LWP 100853/kports)] 0x2917fc29 in .got.plt () from /usr/local/lib/qt4/libQtCore.so.4 (gdb) bt #0 0x2917fc29 in .got.plt () from /usr/local/lib/qt4/libQtCore.so.4 #1 0x01b14c29 in ?? () #2 0xc0ed1029 in ?? () #3 0xbfd97029 in ?? () #4 0xc1a0c