perf/Documentation/tips.txt

1 For a higher level overview, try: perf report --sort comm,dso
2 Sample related events with: perf record -e '{cycles,instructions}:S'
4 Boolean options have negative forms, e.g.: perf report --no-children
5 To not accumulate CPU time of children symbols add --no-children
6 Customize output of perf script with: perf script -F event,ip,sym
7 Generate a script for your data: perf script -g <lang>
10 Search options using a keyword: perf report -h <keyword>
11 Use parent filter to see specific call path: perf report -p <regex>
13 To see list of saved events and attributes: perf evlist -v
14 Use --symfs <dir> if your symbol files are in non-standard locations
15 To see callchains in a more compact form: perf report -g folded
16 To see call chains by final symbol taking CPU time (bottom up) use perf report -G
17 Show individual samples with: perf script
18 Limit to show entries above 5% only: perf report --percent-limit 5
19 Profiling branch (mis)predictions with: perf record -b / perf report
20 To show assembler sample context control flow use perf record -b / perf report --samples 10 and the…
21 To adjust path to source files to local file system use perf report --prefix=... --prefix-strip=...
22 Treat branches as callchains: perf record -b ... ; perf report --branch-history
23 Show estimate cycles per function and IPC in annotate use perf record -b ... ; perf report --total-…
24 To count events every 1000 msec: perf stat -I 1000
25 Print event counts in machine readable CSV format with: perf stat -x\;
26 If you have debuginfo enabled, try: perf report -s sym,srcline
28 For tracepoint events, try: perf report -s trace_fields
29 To record callchains for each sample: perf record -g
30 If call chains don't work try perf record --call-graph dwarf or --call-graph lbr
31 To record every process run by a user: perf record -u <user>
32 To show inline functions in call traces add --inline to perf report
33 To not record events from perf itself add --exclude-perf
34 Skip collecting build-id when recording: perf record -B
35 To change sampling frequency to 100 Hz: perf record -F 100
36 To show information about system the samples were collected on use perf report --header
37 … call graph on one event use perf record -e cpu/cpu-cycles,callgraph=1/,branches ; perf report --s…
38 To set sampling period of individual events use perf record -e cpu/cpu-cycles,period=100001/,cpu/br…
39 To group events which need to be collected together for accuracy use {}: perf record -e {cycles,bra…
40 To compute metrics for samples use perf record -e '{cycles,instructions}' ... ; perf script -F +met…
42 If you prefer Intel style assembly, try: perf annotate -M intel
43 …cting LBR backtraces use --stitch-lbr to handle more than 32 deep entries: perf record --call-grap…
44 For hierarchical output, try: perf report --hierarchy
45 Order by the overhead of source file name and line number: perf report -s srcline
46 System-wide collection from all CPUs: perf record -a
47 Show current config key-value pairs: perf config --list
48 …cessor Trace with samples use perf record -e '{intel_pt//,cycles}' ; perf script --call-trace or -…
49 …g Processor Trace use perf record -e intel_pt// ... ; perf script --call-trace. Then use perf scri…
50 … function latency with Processor Trace use perf record -e intel_pt// ... ; perf script --call-ret-…
51 …with Processor Trace use perf record --filter 'filter func @ program' -e intel_pt//u ./program ; p…
52 Show user configuration overrides: perf config --user --list
53 To add Node.js USDT(User-Level Statically Defined Tracing): perf buildid-cache --add `which node`
55 To browse sample contexts use perf report --sample 10 and select in context menu
56 To separate samples by time use perf report --sort time,overhead,sym
57 To filter subset of samples with report or script add --time X-Y or --cpu A,B,C or --socket-filter …
58 To set sample time separation other than 100ms with --sort time use --time-quantum
59 Add -I to perf record to sample register values, which will be visible in perf report sample contex…
60 To show IPC for sampling periods use perf record -e '{cycles,instructions}:S' and then browse conte…
61 To show context switches in perf report sample context add --switch-events to perf record.
62 To show time in nanoseconds in record/report add --ns
63 To compare hot regions in two workloads use perf record -b -o file ... ; perf diff --stream file1 f…
64 To compare scalability of two workload samples use perf diff -c ratio file1 file2