Commit da231338ec ("perf record: Use an eventfd to wakeup when
done") uses eventfd() to solve a rare race where the setting and
checking of 'done' which add done_fd to pollfd. When draining buffer,
revents of done_fd is 0 and evlist__filter_pollfd function returns a
non-zero value. As a result, perf record does not stop profiling.
The following simple scenarios can trigger this condition:
# sleep 10 &
# perf record -p $!
After the sleep process exits, perf record should stop profiling and exit.
However, perf record keeps running.
If pollfd revents contains only POLLERR or POLLHUP, perf record
indicates that buffer is draining and need to stop profiling. Use
fdarray_flag__nonfilterable() to set done eventfd to nonfilterable
objects, so that evlist__filter_pollfd() does not filter and check done
eventfd.
Fixes: da231338ec ("perf record: Use an eventfd to wakeup when done")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: zhangjinhao2@huawei.com
Link: http://lore.kernel.org/lkml/20210205065001.23252-1-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Detect symbols generated by the OCaml compiler based on their prefix.
Demangle OCaml symbols, returning a newly allocated string (like the
existing Java demangling functionality).
Move a helper function (hex) from tests/code-reading.c to util/string.c
To test:
echo 'Printf.printf "%d\n" (Random.int 42)' > test.ml
perf record ocamlopt.opt test.ml
perf report -d ocamlopt.opt
Signed-off-by: Fabian Hemmer <copy@copy.sh>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LPU-Reference: 20210203211537.b25ytjb6dq5jfbwx@nyu
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
With LTO, there are symbols like these:
/usr/lib/debug/usr/lib64/libantlr4-runtime.so.4.8-4.8-1.4.x86_64.debug
10305: 0000000000955fa4 0 NOTYPE LOCAL DEFAULT 29 Predicate.cpp.2bc410e7
This comes from a runtime/debug split done by the standard way:
objcopy --only-keep-debug $runtime $debug
objcopy --add-gnu-debuglink=$debugfn -R .comment -R .GCC.command.line --strip-all $runtime
perf currently cannot resolve such symbols (relicts of LTO), as section
29 exists only in the debug file (29 is .debug_info). And perf resolves
symbols only against runtime file. This results in all symbols from such
a library being unresolved:
0.38% main2 libantlr4-runtime.so.4.8 [.] 0x00000000000671e0
So try resolving against the debug file first. And only if it fails (the
section has NOBITS set), try runtime file. We can do this, as "objcopy
--only-keep-debug" per documentation preserves all sections, but clears
data of some of them (the runtime ones) and marks them as NOBITS.
The correct result is now:
0.38% main2 libantlr4-runtime.so.4.8 [.] antlr4::IntStream::~IntStream
Note that these LTO symbols are properly skipped anyway as they belong
neither to *text* nor to *data* (is_label && !elf_sec__filter(&shdr,
secstrs) is true).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210217122125.26416-1-jslaby@suse.cz
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The sample structure contains the field 'data_src' which is used to
tell the data operation attributions, e.g. operation type is loading or
storing, cache level, it's snooping or remote accessing, etc. At the
end, the 'data_src' will be parsed by perf mem/c2c tools to display
human readable strings.
This patch is to fill the 'data_src' field in the synthesized samples
base on different types. Currently perf tool can display statistics for
L1/L2/L3 caches but it doesn't support the 'last level cache'. To fit
to current implementation, 'data_src' field uses L3 cache for last level
cache.
Before this commit, perf mem report looks like this:
# Samples: 75K of event 'l1d-miss'
# Total weight : 75951
# Sort order : local_weight,mem,sym,dso,symbol_daddr,dso_daddr,snoop,tlb,locked
#
# Overhead Samples Local Weight Memory access Symbol Shared Object Data Symbol Data Object Snoop TLB access
# ........ ....... ............ ............. ...................... ............. ...................... ........... ..... ..........
#
81.56% 61945 0 N/A [.] 0x00000000000009d8 serial_c [.] 0000000000000000 [unknown] N/A N/A
18.44% 14003 0 N/A [.] 0x0000000000000828 serial_c [.] 0000000000000000 [unknown] N/A N/A
Now on a system with Arm SPE, addresses and access types are displayed:
# Samples: 75K of event 'l1d-miss'
# Total weight : 75951
# Sort order : local_weight,mem,sym,dso,symbol_daddr,dso_daddr,snoop,tlb,locked
#
# Overhead Samples Local Weight Memory access Symbol Shared Object Data Symbol Data Object Snoop TLB access
# ........ ....... ............ ............. ...................... ............. ...................... ........... ..... ..........
#
0.43% 324 0 L1 miss [.] 0x00000000000009d8 serial_c [.] 0x0000ffff80794e00 anon N/A Walker hit
0.42% 322 0 L1 miss [.] 0x00000000000009d8 serial_c [.] 0x0000ffff80794580 anon N/A Walker hit
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: James Clark <james.clark@arm.com>
Tested-by: James Clark <james.clark@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Al Grant <al.grant@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wei Li <liwei391@huawei.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20210211133856.2137-6-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Perf failed to add a kretprobe event with debuginfo of vmlinux which is
compiled by gcc with -fpatchable-function-entry option enabled. The
same issue with kernel module.
Issue:
# perf probe -v 'kernel_clone%return $retval'
......
Writing event: r:probe/kernel_clone__return _text+599624 $retval
Failed to write event: Invalid argument
Error: Failed to add events. Reason: Invalid argument (Code: -22)
# cat /sys/kernel/debug/tracing/error_log
[156.75] trace_kprobe: error: Retprobe address must be an function entry
Command: r:probe/kernel_clone__return _text+599624 $retval
^
# llvm-dwarfdump vmlinux |grep -A 10 -w 0x00df2c2b
0x00df2c2b: DW_TAG_subprogram
DW_AT_external (true)
DW_AT_name ("kernel_clone")
DW_AT_decl_file ("/home/code/linux-next/kernel/fork.c")
DW_AT_decl_line (2423)
DW_AT_decl_column (0x07)
DW_AT_prototyped (true)
DW_AT_type (0x00dcd492 "pid_t")
DW_AT_low_pc (0xffff800010092648)
DW_AT_high_pc (0xffff800010092b9c)
DW_AT_frame_base (DW_OP_call_frame_cfa)
# cat /proc/kallsyms |grep kernel_clone
ffff800010092640 T kernel_clone
# readelf -s vmlinux |grep -i kernel_clone
183173: ffff800010092640 1372 FUNC GLOBAL DEFAULT 2 kernel_clone
# objdump -d vmlinux |grep -A 10 -w \<kernel_clone\>:
ffff800010092640 <kernel_clone>:
ffff800010092640: d503201f nop
ffff800010092644: d503201f nop
ffff800010092648: d503233f paciasp
ffff80001009264c: a9b87bfd stp x29, x30, [sp, #-128]!
ffff800010092650: 910003fd mov x29, sp
ffff800010092654: a90153f3 stp x19, x20, [sp, #16]
The entry address of kernel_clone converted by debuginfo is _text+599624
(0x92648), which is consistent with the value of DW_AT_low_pc attribute.
But the symbolic address of kernel_clone from /proc/kallsyms is
ffff800010092640.
This issue is found on arm64, -fpatchable-function-entry=2 is enabled when
CONFIG_DYNAMIC_FTRACE_WITH_REGS=y;
Just as objdump displayed the assembler contents of kernel_clone,
GCC generate 2 NOPs at the beginning of each function.
kprobe_on_func_entry detects that (_text+599624) is not the entry address
of the function, which leads to the failure of adding kretprobe event.
kprobe_on_func_entry
->_kprobe_addr
->kallsyms_lookup_size_offset
->arch_kprobe_on_func_entry // FALSE
The cause of the issue is that the first instruction in the compile unit
indicated by DW_AT_low_pc does not include NOPs.
This issue exists in all gcc versions that support
-fpatchable-function-entry option.
I have reported it to the GCC community:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98776
Currently arm64 and PA-RISC may enable fpatchable-function-entry option.
The kernel compiled with clang does not have this issue.
FIX:
This GCC issue only cause the registration failure of the kretprobe event
which doesn't need debuginfo. So, stop using debuginfo for retprobe.
map will be used to query the probe function address.
Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: clang-built-linux@googlegroups.com
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Link: http://lore.kernel.org/lkml/20210210062646.2377995-1-Jianlin.Lv@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
dso__load_bfd_symbols() attempts to load a DSO at its original path,
then closes it and loads the file in the debug cache. This is incorrect.
It should ignore the original file and work with only the debug cache.
The original file may have changed or may not even exist, for example if
the debug cache has been transferred to another machine via "perf
archive".
This fix makes it only load the file in the debug cache.
Further notes from Nicholas:
dso__load_bfd_symbols() is called in a loop from dso__load() for a variety
of paths. These are generated by the various DSO_BINARY_TYPEs in the
binary_type_symtab list at the top of util/symbol.c. In each case the
debugfile passed to dso__load_bfd_symbols() is the path to try.
One of those iterations (the first one I believe) passes the original path
as the debugfile. If the file still exists at the original path, this is
the one that ends up being used in case the debugcache was deleted or the
PE file doesn't have a build-id.
A later iteration (BUILD_ID_CACHE) passes debugfile as the file in the
debugcache if it has a build-id. Even if the file was previously loaded at
its original path, (if I understand correctly) this load will override it
so the debugcache file ends up being used.
Committer notes:
So if it fails to find in the cache, it will eventually hope for the
best and look at the path in the local filesystem, which in many cases
is enough.
At some point we need to switch from this "hope for the best" approach
to one that warns the user that there is no guarantee, if no buildid is
present, that just by looking at the pathname the symbolisation will
work.
Signed-off-by: Nicholas Fraser <nfraser@codeweavers.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Huw Davies <huw@codeweavers.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Remi Bernon <rbernon@codeweavers.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Tommi Rantala <tommi.t.rantala@nokia.com>
Cc: Ulrich Czekalla <uczekalla@codeweavers.com>
Link: http://lore.kernel.org/lkml/e58e1237-94ab-e1c9-a7b9-473531906954@codeweavers.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Adrian Hunter
Dave Rigby
Yang Jihong
Jiapeng Chong
Joakim Zhang
Martin Liška
Yang Li
Fabian Hemmer
Namhyung Kim
Jiri Slaby
Arnaldo Carvalho de Melo
Leo Yan
Jianlin Lv
Nicholas Fraser