[PATCH v1]: perf/x86: store user space frame-pointer value on a sample
From: Alexey Budankov
Date: Fri Apr 06 2018 - 08:49:55 EST
Store user space frame-pointer value (BP register) into Perf trace
on a sample for x86_64 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_futex
and 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_futex
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: 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_clean_all_O: cd . && make clean all FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.EB4YTtRbxL DESTDIR=/tmp/tmp.IPhLgudoxW
make_tags_O: cd . && make tags FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.z8RttESyW2 DESTDIR=/tmp/tmp.6Gv8JZOYx3
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.0pRqgxEWLe DESTDIR=/tmp/tmp.ioqNtqIWn3
make_help_O: cd . && make help FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.wNsijVwTQH DESTDIR=/tmp/tmp.jz1T2nM2IK
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.nfZdzepUbZ DESTDIR=/tmp/tmp.DQZlnzHRSX
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.87R85hXnHy DESTDIR=/tmp/tmp.evxqlvqF9Q
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.uZ2uxgsHfH DESTDIR=/tmp/tmp.gK94AuyCSw
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.SbQvlckgpr DESTDIR=/tmp/tmp.BdicQuNJ4I
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.Hs8Fgw58sM DESTDIR=/tmp/tmp.O9xJ46ivch
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.4J4C37PEcX DESTDIR=/tmp/tmp.17KyQdjlJr
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.9T7d972Iq4 DESTDIR=/tmp/tmp.OmhdemgoD0
make_with_babeltrace_O: cd . && make LIBBABELTRACE=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.YAAQ8BJQ47 DESTDIR=/tmp/tmp.ab6vWEz2BH
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.PVn97i2GaD DESTDIR=/tmp/tmp.FtoNcYLuit
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.vXXDkjPncA DESTDIR=/tmp/tmp.6C1TxNjEsK
make_perf_o_O: cd . && make perf.o FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.41vLM9THKV DESTDIR=/tmp/tmp.iRNmuH6HhX
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.s7QM9fH857 DESTDIR=/tmp/tmp.5ksvTXOKFS
make_install_O: cd . && make install FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.AtP0IWbb1q DESTDIR=/tmp/tmp.ALFitlnvys
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.d7Fj07hY9t DESTDIR=/tmp/tmp.lJgh1rAlC8
make_doc_O: cd . && make doc FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.d8zNjEXSK9 DESTDIR=/tmp/tmp.h5deIYBlpA
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.kMK5kEhFxt DESTDIR=/tmp/tmp.gk2k2wXNhl
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.2OFaqPWKaX DESTDIR=/tmp/tmp.UISM6T2OtL
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.8SKo9n8vWp DESTDIR=/tmp/tmp.6fwjE762L1
make_with_clangllvm_O: cd . && make LIBCLANGLLVM=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.22nXtyLNUw DESTDIR=/tmp/tmp.iMc2ET9PEQ
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.9D2ef8yWWg DESTDIR=/tmp/tmp.BigQsiYWgB
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.QvQVtsyo0U DESTDIR=/tmp/tmp.35obmHcXNO
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.QkDnnb6nS0 DESTDIR=/tmp/tmp.UxLWSGZcAb
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.whyhxkgyt5 DESTDIR=/tmp/tmp.Sk5P3IyCfK
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.kZDK82cROR DESTDIR=/tmp/tmp.AuAmKVkSJM
make_pure_O: cd . && make FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.CnnvrI746k DESTDIR=/tmp/tmp.iagYJmBzuk
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.GdYxbYcpa6 DESTDIR=/tmp/tmp.l2Kdlb4nw6
make_install_bin_O: cd . && make install-bin FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.K53lCwDwuc DESTDIR=/tmp/tmp.P054EgzUVW
make_debug_O: cd . && make DEBUG=1 FEATURES_DUMP=/root/abudanko/kernel/tip/tools/perf/BUILD_TEST_FEATURE_DUMP -j8 O=/tmp/tmp.URb8OKvyPH DESTDIR=/tmp/tmp.lEmNtybd4Y
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.AYhs9jZJta DESTDIR=/tmp/tmp.3utydz1YeX
- /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.LUNSZNLI7T DESTDIR=/tmp/tmp.KEOWH9Dlum
OK
make: Leaving directory '/root/abudanko/kernel/tip/tools/perf'
Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
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 | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
index e47b2dbbdef3..9284048cf5b0 100644
--- a/arch/x86/kernel/perf_regs.c
+++ b/arch/x86/kernel/perf_regs.c
@@ -157,6 +157,15 @@ void perf_get_regs_user(struct perf_regs *regs_user,
*/
regs_user_copy->bx = -1;
regs_user_copy->bp = -1;
+ if (user_64bit_mode(user_regs)) {
+ /*
+ * Store user space frame-pointer value on sample
+ * to facilitate stack unwinding for cases when
+ * user space x86_64 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;