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1perf.data directory format2 3DISCLAIMER This is not ABI yet and is subject to possible change4 in following versions of perf. We will remove this5 disclaimer once the directory format soaks in.6 7 8This document describes the on-disk perf.data directory format.9 10The layout is described by HEADER_DIR_FORMAT feature.11Currently it holds only version number (0):12 13 HEADER_DIR_FORMAT = 2414 15 struct {16 uint64_t version;17 }18 19The current only version value 0 means that:20 - there is a single perf.data file named 'data' within the directory.21 e.g.22 23 $ tree -ps perf.data24 perf.data25 └── [-rw------- 25912] data26 27Future versions are expected to describe different data files28layout according to special needs.29 30Currently the only 'perf record' option to output to a directory is31the --kcore option which puts a copy of /proc/kcore into the directory.32e.g.33 34 $ sudo perf record --kcore uname35 Linux36 [ perf record: Woken up 1 times to write data ]37 [ perf record: Captured and wrote 0.015 MB perf.data (9 samples) ]38 $ sudo tree -ps perf.data39 perf.data40 ├── [-rw------- 23744] data41 └── [drwx------ 4096] kcore_dir42 ├── [-r-------- 6731125] kallsyms43 ├── [-r-------- 40230912] kcore44 └── [-r-------- 5419] modules45 46 1 directory, 4 files47 $ sudo perf script -v48 build id event received for vmlinux: 1eaa285996affce2d74d8e66dcea09a80c9941de49 build id event received for [vdso]: 8bbaf5dc62a9b644b4d4e4539737e104e4a8454150 build id event received for /lib/x86_64-linux-gnu/libc-2.28.so: 5b157f49586a3ca84d55837f97ff466767dd344551 Samples for 'cycles' event do not have CPU attribute set. Skipping 'cpu' field.52 Using CPUID GenuineIntel-6-8E-A53 Using perf.data/kcore_dir/kcore for kernel data54 Using perf.data/kcore_dir/kallsyms for symbols55 perf 15316 2060795.480902: 1 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux)56 perf 15316 2060795.480906: 1 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux)57 perf 15316 2060795.480908: 7 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux)58 perf 15316 2060795.480910: 119 cycles: ffffffffa2caa54a native_write_msr+0xa (vmlinux)59 perf 15316 2060795.480912: 2109 cycles: ffffffffa2c9b7b0 native_apic_msr_write+0x0 (vmlinux)60 perf 15316 2060795.480914: 37606 cycles: ffffffffa2f121fe perf_event_addr_filters_exec+0x2e (vmlinux)61 uname 15316 2060795.480924: 588287 cycles: ffffffffa303a56d page_counter_try_charge+0x6d (vmlinux)62 uname 15316 2060795.481067: 2261945 cycles: ffffffffa301438f kmem_cache_free+0x4f (vmlinux)63 uname 15316 2060795.481643: 2172167 cycles: 7f1a48c393c0 _IO_un_link+0x0 (/lib/x86_64-linux-gnu/libc-2.28.so)64