Re: [CentOS] Does sprof work on CentOS5?

Filipe Brandenburger wrote:

Acutally I have no idea of what sprof is or does, but from the error

Let me tell you about sprof, then, because it is fantastic!

Of course, it would be even better if it worked.

It is a statistical profiler for shared object libraries that (presumably) works by sampling the position of the program counter every now and again. All you need to do is set the value of LD_PROFILE to the name of the .so and statistics will get dumped to a file in /var/tmp.

You can then use sprof to build a profile from those stats in the same way that gprof does from a gmon.out file.

But it's much better than gprof as you don't have to compile with special flags which cause code to get inserted and distorts the timing of your program anyway. And as it profiles .so files it also allows you to easily profile python modules, for example, where you don't want to recompile the main program.

Unfortunately, there does not seem to be much information about it on the internet. It makes me wonder if there is an alternative which has superceeded it (I see oprofile, but it looks a good deal more difficult to use).

message above it seems sprof cannot find your library because it is not in the default library search path. Try this:

$ LD_LIBRARY_PATH=. sprof libmy.so /var/tmp/libmy.so.profile

Let us know how that goes.

No luck with that, I'm afraid:

$ LD_LIBRARY_PATH=. sprof libmy.so /var/tmp/libmy.so.profile sprof: failed to load shared object `libmy.so'

I've tried all sorts to try and coax the program to accept the files - I wonder if it might not just be an unhelpful error message and something else is failing. I have a strace here in case anyone can understand what is going on (is it some locale setting that it doesn't like, perhaps, I don't know much about that stuff - it doesn't seem to attempt to open anything like libmy.so at all):

execve("/usr/bin/sprof", ["sprof", "libmy.so", "/var/tmp/libmy.so.profile"], [/* 39 vars */]) = 0 brk(0) = 0x8c78000 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7fd7000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/xorg/tls/i686/sse2/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xorg/tls/i686/sse2", 0xbf83ced8) = -1 ENOENT (No such file or directory) open("/usr/lib/xorg/tls/i686/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xorg/tls/i686", 0xbf83ced8) = -1 ENOENT (No such file or directory) open("/usr/lib/xorg/tls/sse2/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xorg/tls/sse2", 0xbf83ced8) = -1 ENOENT (No such file or directory) open("/usr/lib/xorg/tls/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xorg/tls", 0xbf83ced8) = -1 ENOENT (No such file or directory) open("/usr/lib/xorg/i686/sse2/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xorg/i686/sse2", 0xbf83ced8) = -1 ENOENT (No such file or directory) open("/usr/lib/xorg/i686/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xorg/i686", 0xbf83ced8) = -1 ENOENT (No such file or directory) open("/usr/lib/xorg/sse2/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xorg/sse2", 0xbf83ced8) = -1 ENOENT (No such file or directory) open("/usr/lib/xorg/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xorg", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 open("/etc/ld.so.cache", O_RDONLY) = 3 fstat64(3, {st_mode=S_IFREG|0644, st_size=80005, ...}) = 0 mmap2(NULL, 80005, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7fc3000 close(3) = 0 open("/lib/libdl.so.2", O_RDONLY) = 3 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0PJ\251\0004\0\0\0"..., 512) = 512 fstat64(3, {st_mode=S_IFREG|0755, st_size=16428, ...}) = 0 mmap2(0xa94000, 12408, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xa94000 mmap2(0xa96000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1) = 0xa96000 close(3) = 0 open("/usr/lib/xorg/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0000\277\223\0004\0\0\0"..., 512) = 512 fstat64(3, {st_mode=S_IFREG|0755, st_size=1597968, ...}) = 0 mmap2(0x926000, 1320356, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x926000 mmap2(0xa63000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x13c) = 0xa63000 mmap2(0xa66000, 9636, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xa66000 close(3) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7fc2000 set_thread_area({entry_number:-1 -> 6, base_addr:0xb7fc26c0, limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0, useable:1}) = 0 mprotect(0xa96000, 4096, PROT_READ) = 0 mprotect(0xa63000, 8192, PROT_READ) = 0 mprotect(0x922000, 4096, PROT_READ) = 0 munmap(0xb7fc3000, 80005) = 0 brk(0) = 0x8c78000 brk(0x8c99000) = 0x8c99000 open("/usr/lib/locale/locale-archive", O_RDONLY|O_LARGEFILE) = 3 fstat64(3, {st_mode=S_IFREG|0644, st_size=56454464, ...}) = 0 mmap2(NULL, 2097152, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7dc2000 mmap2(NULL, 884736, PROT_READ, MAP_PRIVATE, 3, 0x1e1) = 0xb7cea000 mmap2(NULL, 4096, PROT_READ, MAP_PRIVATE, 3, 0x6d1) = 0xb7ce9000 close(3) = 0 open("/usr/share/locale/locale.alias", O_RDONLY) = 3 fstat64(3, {st_mode=S_IFREG|0644, st_size=2528, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7ce8000 read(3, "# Locale name alias data base.\n#"..., 4096) = 2528 read(3, "", 4096) = 0 close(3) = 0 munmap(0xb7ce8000, 4096) = 0 open("/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory) write(2, "sprof: ", 7sprof: ) = 7 write(2, "failed to load shared object `li"..., 39failed to load shared object `libmy.so') = 39 write(2, "\n", 1 ) = 1 exit_group(1) = ?