Re^2: memory usage on x86

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Re^3: memory usage on x86_64 by Eliya (Vicar) on Feb 16, 2012 at 10:43 UTC
And it's still doesn't clear for me, is so much virtual memory requested by perl on 64-bit system is a bug in perl, or correct behaviour. If you have doubts things are as they should be, you can investigate the virtual memory mappings of the process via `/proc/<PID>/maps` (or `/proc/self/maps` from within the process). See also `proc(5)` for a short explanation of the columns. The following snippet might help with computing sizes: `#!/usr/bin/perl open my $maps, "<", "/proc/self/maps" or die $!; my $sum; while (<$maps>) { /^(\S+)-(\S+)/; my $size = hex($2)-hex($1); $sum += $size; printf "%8d : %s", $size, $_; } printf "total: %dk\n", $sum/1024;` [download] On my current system (64-bit openSUSE 11.1, Perl 5.12.3), it shows 1454080 : 00400000-00563000 r-xp 00000000 08:03 1209182 + /usr/local/perl/5.12.3/bin/perl 4096 : 00762000-00763000 r--p 00162000 08:03 1209182 + /usr/local/perl/5.12.3/bin/perl 16384 : 00763000-00767000 rw-p 00163000 08:03 1209182 + /usr/local/perl/5.12.3/bin/perl 270336 : 00767000-007a9000 rw-p 00767000 00:00 0 + [heap] 1372160 : 7fcc9341c000-7fcc9356b000 r-xp 00000000 08:03 960813 + /lib64/libc-2.9.so 2097152 : 7fcc9356b000-7fcc9376b000 ---p 0014f000 08:03 960813 + /lib64/libc-2.9.so 16384 : 7fcc9376b000-7fcc9376f000 r--p 0014f000 08:03 960813 + /lib64/libc-2.9.so 4096 : 7fcc9376f000-7fcc93770000 rw-p 00153000 08:03 960813 + /lib64/libc-2.9.so 20480 : 7fcc93770000-7fcc93775000 rw-p 7fcc93770000 00:00 0 90112 : 7fcc93775000-7fcc9378b000 r-xp 00000000 08:03 960839 + /lib64/libpthread-2.9.so 2097152 : 7fcc9378b000-7fcc9398b000 ---p 00016000 08:03 960839 + /lib64/libpthread-2.9.so 4096 : 7fcc9398b000-7fcc9398c000 r--p 00016000 08:03 960839 + /lib64/libpthread-2.9.so 4096 : 7fcc9398c000-7fcc9398d000 rw-p 00017000 08:03 960839 + /lib64/libpthread-2.9.so 16384 : 7fcc9398d000-7fcc93991000 rw-p 7fcc9398d000 00:00 0 8192 : 7fcc93991000-7fcc93993000 r-xp 00000000 08:03 960847 + /lib64/libutil-2.9.so 2093056 : 7fcc93993000-7fcc93b92000 ---p 00002000 08:03 960847 + /lib64/libutil-2.9.so 4096 : 7fcc93b92000-7fcc93b93000 r--p 00001000 08:03 960847 + /lib64/libutil-2.9.so 4096 : 7fcc93b93000-7fcc93b94000 rw-p 00002000 08:03 960847 + /lib64/libutil-2.9.so 53248 : 7fcc93b94000-7fcc93ba1000 r-xp 00000000 08:03 960817 + /lib64/libcrypt-2.9.so 2097152 : 7fcc93ba1000-7fcc93da1000 ---p 0000d000 08:03 960817 + /lib64/libcrypt-2.9.so 4096 : 7fcc93da1000-7fcc93da2000 r--p 0000d000 08:03 960817 + /lib64/libcrypt-2.9.so 4096 : 7fcc93da2000-7fcc93da3000 rw-p 0000e000 08:03 960817 + /lib64/libcrypt-2.9.so 188416 : 7fcc93da3000-7fcc93dd1000 rw-p 7fcc93da3000 00:00 0 348160 : 7fcc93dd1000-7fcc93e26000 r-xp 00000000 08:03 960821 + /lib64/libm-2.9.so 2093056 : 7fcc93e26000-7fcc94025000 ---p 00055000 08:03 960821 + /lib64/libm-2.9.so 4096 : 7fcc94025000-7fcc94026000 r--p 00054000 08:03 960821 + /lib64/libm-2.9.so 4096 : 7fcc94026000-7fcc94027000 rw-p 00055000 08:03 960821 + /lib64/libm-2.9.so 8192 : 7fcc94027000-7fcc94029000 r-xp 00000000 08:03 960819 + /lib64/libdl-2.9.so 2097152 : 7fcc94029000-7fcc94229000 ---p 00002000 08:03 960819 + /lib64/libdl-2.9.so 4096 : 7fcc94229000-7fcc9422a000 r--p 00002000 08:03 960819 + /lib64/libdl-2.9.so 4096 : 7fcc9422a000-7fcc9422b000 rw-p 00003000 08:03 960819 + /lib64/libdl-2.9.so 86016 : 7fcc9422b000-7fcc94240000 r-xp 00000000 08:03 960824 + /lib64/libnsl-2.9.so 2093056 : 7fcc94240000-7fcc9443f000 ---p 00015000 08:03 960824 + /lib64/libnsl-2.9.so 4096 : 7fcc9443f000-7fcc94440000 r--p 00014000 08:03 960824 + /lib64/libnsl-2.9.so 4096 : 7fcc94440000-7fcc94441000 rw-p 00015000 08:03 960824 + /lib64/libnsl-2.9.so 8192 : 7fcc94441000-7fcc94443000 rw-p 7fcc94441000 00:00 0 1253376 : 7fcc94443000-7fcc94575000 r-xp 00000000 08:03 906609 + /usr/lib64/libdb-4.5.so 2097152 : 7fcc94575000-7fcc94775000 ---p 00132000 08:03 906609 + /usr/lib64/libdb-4.5.so 12288 : 7fcc94775000-7fcc94778000 r--p 00132000 08:03 906609 + /usr/lib64/libdb-4.5.so 12288 : 7fcc94778000-7fcc9477b000 rw-p 00135000 08:03 906609 + /usr/lib64/libdb-4.5.so 122880 : 7fcc9477b000-7fcc94799000 r-xp 00000000 08:03 960806 + /lib64/ld-2.9.so 28672 : 7fcc94922000-7fcc94929000 r--s 00000000 08:03 919953 + /usr/lib64/gconv/gconv-modules.cache 225280 : 7fcc94929000-7fcc94960000 r--p 00000000 08:03 1067394 + /usr/lib/locale/de_DE/LC_CTYPE 16384 : 7fcc94960000-7fcc94964000 rw-p 7fcc94960000 00:00 0 8192 : 7fcc94996000-7fcc94998000 rw-p 7fcc94996000 00:00 0 4096 : 7fcc94998000-7fcc94999000 r--p 0001d000 08:03 960806 + /lib64/ld-2.9.so 4096 : 7fcc94999000-7fcc9499a000 rw-p 0001e000 08:03 960806 + /lib64/ld-2.9.so 86016 : 7fffb8343000-7fffb8358000 rw-p 7ffffffe9000 00:00 0 + [stack] 4096 : 7fffb83b4000-7fffb83b5000 r-xp 7fffb83b4000 00:00 0 + [vdso] 4096 : ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 + [vsyscall] total: 22032k [download] This should correspond to the VSZ as reported by `ps`: `$ /usr/bin/perl -e 'system "ps -p $$ -o rss,vsz,comm"' RSS VSZ COMMAND 1796 22032 perl` [download] As you can see, it's mostly mappings to libraries. But as I already mentioned, a virtual memory mapping doesn't mean it's also using real physical memory... See also `mmap(2)`. And maybe Understanding Memory and Understanding The Linux Virtual Memory Manager (PDF, 730p.) for further reading (I just had those two links within reach — Google's (or DDG's) index knows more fine documents on the subject :)	[reply] [d/l] [select]
Re^4: memory usage on x86_64 by powerman (Friar) on Feb 16, 2012 at 11:00 UTC
Thanks. Looks like on 64-bit there is extra line for each library with flags "---p" using each about 2MB, 5 such libraries add about 10MB. So, looks like this issue have nothing with perl itself. Anyway, do you know what these extra lines mean?	[reply]