- echo 1 > /proc/sys/vm/block_dump
The above command sets a sysctl to cause the kernel to log all disk writes. Below is a sample of the output from it. Beware that there is a lot of data.
Jan 10 09:05:53 aeon kernel: kjournald(1048): WRITE block XXX152 on dm-6
Jan 10 09:05:53 aeon kernel: kjournald(1048): WRITE block XXX160 on dm-6
Jan 10 09:05:53 aeon kernel: kjournald(1048): WRITE block XXX168 on dm-6
Jan 10 09:05:54 aeon kernel: kpowersave(5671): READ block XXX384 on dm-7
Jan 10 09:05:54 aeon kernel: kpowersave(5671): READ block XXX400 on dm-7
Jan 10 09:05:54 aeon kernel: kpowersave(5671): READ block XXX408 on dm-7
Jan 10 09:05:54 aeon kernel: bash(5803): dirtied inode XXXXXX1943 (block_dump) on proc - Prefixing a bash command with ‘ ‘ will prevent a ! operator from running it. For example if you had just entered the command ” ls -al /” then “!l” would not repeat it but would instead match the preceeding command that started with a ‘l’. On SLES-10 a preceeding space also makes the command not appear in
the history while on Debian/etch it does (both run Bash 3.1). - LD_PRELOAD=/lib/libmemusage.so ls > /dev/null
The above LD_PRELOAD will cause a dump to stderr of data about all memory allocations performed by the program in question. Below is a sample of the output.
Memory usage summary: heap total: 28543, heap peak: 20135, stack peak: 9844 total calls total memory failed calls malloc| 85 28543 0 realloc| 11 0 0 (in place: 11, dec: 11) calloc| 0 0 0 free| 21 12107 Histogram for block sizes: 0-15 29 30% ================================================== 16-31 5 5% ======== 32-47 10 10% ================= 48-63 14 14% ======================== 64-79 4 4% ====== 80-95 1 1% = 96-111 20 20% ================================== 112-127 2 2% === 208-223 1 1% = 352-367 4 4% ====== 384-399 1 1% = 480-495 1 1% = 1536-1551 1 1% = 4096-4111 1 1% = 4112-4127 1 1% = 12800-12815 1 1% =
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some random Linux tipsComments are closed. |
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