: perf/x86: expose user space frame-pointer value on a sample
PATCH RESEND v2 1/1 : perf/x86: expose user space frame-pointer value on a sample
Store user space frame-pointer value (BP register) into Perf trace on a sample for a process so the value becomes available when unwinding call stacks for functions gaining event samples.
Test executable for the example below was compiled with frame pointer support enabled:
g++ -o futex-fp -fpermissive --no-omit-frame-pointer futex.c
and profiled using:
tools/perf/perf record --user-regs=IP,SP,BP \ -g --call-graph=dwarf,1024 -e cycles -- ./futex-fp
Output of
tools/perf/perf report -i perf.data --stdio
demonstrates the effect of the patch change so before saving BP value on a sample we have several frames missing above main function frame:
# Samples: 138K of event 'cpu-cycles'
# Event count (approx.): 92713835335
#
# Children Self Command Shared Object Symbol
# ........ ........ ........ ................ ..........................
#
96.15% 0.72% futex-fp futex-fp [.] main
|
|--95.43%--main
| |
| |--71.56%--syscall
| | |
| | |--57.28%--entry_SYSCALL_64_after_hwframe
| | | |
| | | --56.95%--do_syscall_64
| | | |
| | | --55.77%--sys_futexand after saving BP value on a sample we have expected
_start
__libc_start_main
frames unwound:
# Samples: 128K of event 'cpu-cycles'
# Event count (approx.): 85349981034
#
# Children Self Command Shared Object Symbol
# ........ ........ ........ ................ ..................
#
95.83% 0.00% futex-fp futex-fp [.] _start
|
==> ---_start
==> __libc_start_main
main
|
|--71.28%--syscall
| |
| |--55.67%--entry_SYSCALL_64
| | |
| | --55.40%--do_syscall_64
| | |
| | --54.21%--sys_futexTesting results:
tools/perf/perf test
1: vmlinux symtab matches kallsyms : Ok 2: Detect openat syscall event : Ok 3: Detect openat syscall event on all cpus : Ok 4: Read samples using the mmap interface : Ok 5: Test data source output : Ok 6: Parse event definition strings : Ok 7: Simple expression parser : Ok 8: PERF_RECORD_* events & perf_sample fields : Ok 9: Parse perf pmu format : Ok 10: DSO data read : Ok 11: DSO data cache : Ok 12: DSO data reopen : Ok 13: Roundtrip evsel->name : Ok 14: Parse sched tracepoints fields : Ok 15: syscalls:sys_enter_openat event fields : Ok 16: Setup struct perf_event_attr : Skip 17: Match and link multiple hists : Ok 18: 'import perf' in python : FAILED! 19: Breakpoint overflow signal handler : Ok 20: Breakpoint overflow sampling : Ok 21: Breakpoint accounting : Ok 22: Number of exit events of a simple workload : Ok 23: Software clock events period values : Ok 24: Object code reading : Ok 25: Sample parsing : Ok 26: Use a dummy software event to keep tracking : Ok 27: Parse with no sample_id_all bit set : Ok 28: Filter hist entries : Ok 29: Lookup mmap thread : Ok 30: Share thread mg : Ok 31: Sort output of hist entries : Ok 32: Cumulate child hist entries : Ok 33: Track with sched_switch : Ok 34: Filter fds with revents mask in a fdarray : Ok 35: Add fd to a fdarray, making it autogrow : Ok 36: kmod_path__parse : Ok 37: Thread map : Ok 38: LLVM search and compile : 38.1: Basic BPF llvm compile : Skip 38.2: kbuild searching : Skip 38.3: Compile source for BPF prologue generation : Skip 38.4: Compile source for BPF relocation : Skip 39: Session topology : Ok 40: BPF filter : 40.1: Basic BPF filtering : Skip 40.2: BPF pinning : Skip 40.3: BPF prologue generation : Skip 40.4: BPF relocation checker : Skip 41: Synthesize thread map : Ok 42: Remove thread map : Ok 43: Synthesize cpu map : Ok 44: Synthesize stat config : Ok 45: Synthesize stat : Ok 46: Synthesize stat round : Ok 47: Synthesize attr update : Ok 48: Event times : Ok 49: Read backward ring buffer : Ok 50: Print cpu map : Ok 51: Probe SDT events : Ok 52: is_printable_array : Ok 53: Print bitmap : Ok 54: perf hooks : Ok 55: builtin clang support : Skip (not compiled in) 56: unit_number__scnprintf : Ok 57: mem2node : Ok 58: x86 rdpmc : Ok 59: Convert perf time to TSC : Ok 60: DWARF unwind : Ok 61: x86 instruction decoder - new instructions : Ok 62: Use vfs_getname probe to get syscall args filenames : Ok 63: Add vfs_getname probe to get syscall args filenames : Ok
64: Check open filename arg using perf trace + vfs_getname: Ok
65: probe libc's inet_pton & backtrace it with ping : Ok
make -C tools/perf/ build-test
make: Entering directory '/root/abudanko/kernel/tip/tools/perf'
- tarpkg: ./tests/perf-targz-src-pkg .
- /root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP: cd . && make FEATURE_DUMP_COPY=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP feature-dump cd . && make FEATURE_DUMP_COPY=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP feature-dump
make_util_map_o_O: cd . && make util/map.o FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.hCniCh5IOV DESTDIR=/tmp/tmp.pE0ZNthwCF
make_install_prefix_slash_O: cd . && make install prefix=/tmp/krava/ FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.aug1Rs4tNf DESTDIR=/tmp/tmp.Nr57uRH4a7
make_no_libunwind_O: cd . && make NO_LIBUNWIND=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.K6mNdV9ny7 DESTDIR=/tmp/tmp.rJ4MiEneK3
make_install_bin_O: cd . && make install-bin FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.4qmyWxqRIq DESTDIR=/tmp/tmp.fQ9pvBSPbK
make_no_libbionic_O: cd . && make NO_LIBBIONIC=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.Ja0slX338A DESTDIR=/tmp/tmp.QoqYxqLoLM
make_no_libbpf_O: cd . && make NO_LIBBPF=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.M4cGuRET89 DESTDIR=/tmp/tmp.yRbVHtN25b
make_doc_O: cd . && make doc FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.vit59hhoQw DESTDIR=/tmp/tmp.Pdf8YRdUZ6
make_no_slang_O: cd . && make NO_SLANG=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.HVyxNOBsAd DESTDIR=/tmp/tmp.a0faga36nq
make_no_libdw_dwarf_unwind_O: cd . && make NO_LIBDW_DWARF_UNWIND=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.wmv42sG9uM DESTDIR=/tmp/tmp.QqGhSX5KBD
make_clean_all_O: cd . && make clean all FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.EXQULIs1Lz DESTDIR=/tmp/tmp.R7rWtWOfbj
make_no_gtk2_O: cd . && make NO_GTK2=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.Ic7nrL0sJw DESTDIR=/tmp/tmp.CG4zzMpTRo
make_util_pmu_bison_o_O: cd . && make util/pmu-bison.o FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.SlTUvMOKNC DESTDIR=/tmp/tmp.EPHTxRCqhZ
make_help_O: cd . && make help FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.8ERtFQpSgy DESTDIR=/tmp/tmp.qm6slgq3vY
make_no_libpython_O: cd . && make NO_LIBPYTHON=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.nBDottRklF DESTDIR=/tmp/tmp.wa3Y3kbyuj
make_no_auxtrace_O: cd . && make NO_AUXTRACE=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.DUdGkNlbTo DESTDIR=/tmp/tmp.hCudQY48Pl
make_no_libaudit_O: cd . && make NO_LIBAUDIT=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.R881i6xKAm DESTDIR=/tmp/tmp.93owQPSDcX
make_no_scripts_O: cd . && make NO_LIBPYTHON=1 NO_LIBPERL=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.reGc8rOYV1 DESTDIR=/tmp/tmp.B6QViKjMvW
make_with_babeltrace_O: cd . && make LIBBABELTRACE=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.FhQXwacUez DESTDIR=/tmp/tmp.I3nVzmrMkw
- /root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP_STATIC: cd . && make FEATURE_DUMP_COPY=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP_STATIC LDFLAGS='-static' feature-dump
cd . && make FEATURE_DUMP_COPY=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP_STATIC LDFLAGS='-static' feature-dump
make_static_O: cd . && make LDFLAGS=-static FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP_STATIC -j8 O=/tmp/tmp.WAd4qqaobf DESTDIR=/tmp/tmp.HQGv9RVti6
make_tags_O: cd . && make tags FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.4exbvnNqL7 DESTDIR=/tmp/tmp.egmegRFPBa
make_no_backtrace_O: cd . && make NO_BACKTRACE=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.EVUZhEZdL1 DESTDIR=/tmp/tmp.IU2Hw5iXV9
make_debug_O: cd . && make DEBUG=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.82NeGzBeKh DESTDIR=/tmp/tmp.0nDEL657DW
make_no_ui_O: cd . && make NO_NEWT=1 NO_SLANG=1 NO_GTK2=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.WPsaGPykuA DESTDIR=/tmp/tmp.BE2i6xrlcz
make_minimal_O: cd . && make NO_LIBPERL=1 NO_LIBPYTHON=1 NO_NEWT=1 NO_GTK2=1 NO_DEMANGLE=1 NO_LIBELF=1 NO_LIBUNWIND=1 NO_BACKTRACE=1 NO_LIBNUMA=1 NO_LIBAUDIT=1 NO_LIBBIONIC=1 NO_LIBDW_DWARF_UNWIND=1 NO_AUXTRACE=1 NO_LIBBPF=1 NO_LIBCRYPTO=1 NO_SDT=1 NO_JVMTI=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.mqwTCtkYMZ DESTDIR=/tmp/tmp.HAE2gO2Qcc
make_install_prefix_O: cd . && make install prefix=/tmp/krava FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.i9spzN3Ffn DESTDIR=/tmp/tmp.HZaM1gdpnX
make_no_libelf_O: cd . && make NO_LIBELF=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.yXvEPnLS3l DESTDIR=/tmp/tmp.wDVGcoV12j
make_pure_O: cd . && make FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.Lyk3dyMDUS DESTDIR=/tmp/tmp.X7yG8O8oPZ
make_no_newt_O: cd . && make NO_NEWT=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.u2rAAJ77BP DESTDIR=/tmp/tmp.ZO73ixWJ4R
make_perf_o_O: cd . && make perf.o FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.PzkhlImKTo DESTDIR=/tmp/tmp.9Z5E1d0ADO
make_install_O: cd . && make install FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.LeTMZGGxYu DESTDIR=/tmp/tmp.i0QyvEIrk0
make_no_libnuma_O: cd . && make NO_LIBNUMA=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.FBhx6NatXS DESTDIR=/tmp/tmp.1LrUcc5i7s
make_no_libperl_O: cd . && make NO_LIBPERL=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.iPoY2Rkjbw DESTDIR=/tmp/tmp.kUsnd09yOc
make_with_clangllvm_O: cd . && make LIBCLANGLLVM=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.yA8pvPEJHH DESTDIR=/tmp/tmp.XwY7J5Etvy
make_no_demangle_O: cd . && make NO_DEMANGLE=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.NARFUtnpY0 DESTDIR=/tmp/tmp.dR62bKhig0OK
make: Leaving directory '/root/abudanko/kernel/tip/tools/perf'
Signed-off-by Alexey Budankov <[email protected]>
---
Changes in v2:
- lifted restriction on frame pointer architecture so it's value is provided as for i386 as for x86_64 processes
MAINTAINERS file lacks references to appropriate folks for reviewing
changes at arch/x86/kernel/perf_regs.c so probably it makes sense to update the file as well in this respect.
--- arch/x86/kernel/perf_regs.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
arch/x86/kernel/perf_regs.c +7 -1
@@ -156,7 +156,13 @@ void perf_get_regs_user(struct perf_regs *regs_user,* Most system calls don't save these registers, don't report them. */ regs_user_copy->bx =-1 ; - regs_user_copy->bp =-1 ; +/* +* Store user space frame-pointer value on sample +* to facilitate stack unwinding for cases when +* user space executable code has such support +* enabled at compile time; +*/ + regs_user_copy->bp = user_regs->bp; regs_user_copy->r12 =-1 ; regs_user_copy->r13 =-1 ; regs_user_copy->r14 =-1 ;