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Diffstat (limited to 'debug.txt')
| -rw-r--r-- | debug.txt | 172 |
1 files changed, 0 insertions, 172 deletions
diff --git a/debug.txt b/debug.txt deleted file mode 100644 index 87ca483..0000000 --- a/debug.txt +++ /dev/null @@ -1,172 +0,0 @@ -# debugging --------------------------------------------------------------------------------- - -# -# strace(1) -# - -strace [OPTS] [ELF] - -f .......... follow child processes on fork(2) - -p <pid> .... attach to running process - -s <size> ... max string size (default: 32) - -e <expr> ... expression for trace filtering - -o <file> ... log output into <file> - -c .......... dump syscall statitics at the end - -useful <expr>: - trace=syscall[,syscall] .... trace only syscall listed - trace=file ................. trace all syscall that take a filename as arg - trace=process .............. trace process management related syscalls - trace=signal ............... trace signal related syscalls - signal ..................... trace signals delivered to the process - -use cases: -- trace 'open & socket' syscalls for a running process + childs -strace -f -p <pid> -e trace=open,socket - -- trace signals delivered to a running process -strace -f -p <pid> -e signal - - -# -# lsof(8) -# - -lsof - -a ......... AND slection filters instead ORing (OR: default) - -p <pid> ... list open file descriptors for process - +fg ........ show file flags for file descripros - -n ......... don't convert network addr to hostnames - -P ......... dont' convert network port to know service names - -i <@h[:p]>. show connections to h (hostname|ip addr) with optional port p - -file flags: - R/W/RW ..... read/write/read-write - CR ......... create - AP ......... append - TR ......... truncate - -uase cases: -- show open files with file flags -lsof +fg -p <pid> - -- show open tcp connections from user -lsof -a -u $USER -i tcp - -- show open connections to 'localhost' for user -lsof -a -u $USER -i @localhost - -# -# pmap(1) -# - -pmap <pid> - ............. dump virtual memory map of process. - compared to /proc/<pid>/maps it shows the size of the mappings - - -# -# pstack(1) -# - -pstack <pid> - ............. dump current stack of process + threads - - -# -# pidstat(1) -# - -# trace minor/major page faults -pidstat -r -p <pid> [interval] - minor_pagefault: happens when the page needed is already in memory but not - allocated to the faulting process, in that case the kernel - only has to create a new page-table entry pointing to the - shared physical page - major_pagefault: happends when the page needed is NOT in memory, the kernel - has to create a new page-table entry and populate the - physical page - - -# -# /usr/bin/time(1) -# - -# statistics of process run -/usr/bin/time -v <cmd> - - -# -# perf(1) -# - -# get supported events -perf list - ......... show supported hw/sw events - -perf stat - -p <pid> .. show stats for running process - -I <ms> ... show stats periodically over interval <ms> - -e <ev> ... filter for events - -perf top - -p <pid> .. show stats for running process - -F <hz> ... sampling frequency - -K ........ hide kernel threads - -perf record - -p <pid> ............... record stats for running process - -F <hz> ................ sampling frequency - --call-graph <method> .. [fp, dwarf, lbr] method how to caputre backtrace - fp : use frame-pointer, need -fno-omit-frame-pointer - dwarf: use .cfi debug information - lbr : use hardware last branch record facility - -g ..................... short-hand for --call-graph fp - -e <ev> ................ filter for events - -perf report - -n .................... annotate symbols with nr of samples - --stdio ............... report to stdio, if not presen tui mode - -g graph,0.5,caller ... show caller based call chains with value >0.5 - -useful <ev>: - page-faults - minor-faults - major-faults - cpu-cycles` - task-clock - - -# -# flamegraph(https://github.com/brendangregg/FlameGraph) -# - -# flamegraph for single event trace -perf record -g -p <pid> -e cpu-cycles -perf script | FlameGraph/stackcollapse-perf.pl | FlameGraph/flamegraph.pl > cycles-flamegraph.svg - -# flamegraphs for multiple events trace -perf record -g -p <pid> -e cpu-cycles,page-faults -perf script --per-event-dump -# fold & generate as above -# - -# -# OProfile -# - -operf -g -p <pid> - -g ...... caputre call-graph information - -opreport [opt] FILE - NOOPT ... show time spent per binary image - -l ...... show time spent per symbol - -c ...... show callgraph information (see below) - -a ...... add column with time spent accumulated over child nodes - -ophelp - NOOPT ... show supported hw/sw events - --------------------------------------------------------------------------------- -vim:ft=help:sts=2:et:tw=80:cc=80:fo+=t - |