Today, when a JSON file fails parsing the build continues, but there are
no json files built in, which is difficult to debug later. Make the
build stop on a parse error instead.
v2: Add fixes from Sukadev. Now we handle architectures
with no JSON events correctly. And fix some stale comments.
Committer note:
Tested by running the cross build container tests, that were all failing
for v1.
In this example, The "main div.c:39 (COND_BWD CROSS_2M predicted:49.7%)"
is "to" of branch and "main div.c:44 (cycles:1)" is "from" of branch.
It should be easier for understanding than before.
Jin Yao [Mon, 8 May 2017 10:43:02 +0000 (18:43 +0800)]
perf report: Make --branch-history work without callgraphs(-g) option in perf record
perf record -b -g <command>
perf report --branch-history
This merges the LBRs with the callgraphs.
However it would be nice if it also works without callgraphs (-g) set in
perf record, so that only the LBRs are displayed. But currently perf
report errors in this case. For example,
perf record -b <command>
perf report --branch-history
Error:
Selected -g or --branch-history but no callchain data. Did
you call 'perf record' without -g?
This patch displays the LBRs only even if callgraphs(-g) is not enabled
in perf record.
Change log:
v2: According to Milian Wolff's comment, change the obsolete error
message. Now the error message is:
┌─Error:─────────────────────────────────────┐
│Selected -g or --branch-history. │
│But no callchain or branch data. │
│Did you call 'perf record' without -g or -b?│
│ │
│ │
│Press any key... │
└────────────────────────────────────────────┘
When passing the last parameter to hists__fprintf,
changes "|" to "||".
perf script python: Generate hooks with additional argument
Modify the signature of tracepoint specific and trace_unhandled hooks to
add the perf_sample dict as a new argument.
Create a python helper function to print a dictionary.
perf script python: Add perf_sample dict to tracepoint handlers
The process_event python hook receives a dict with all perf_sample
entries, but the tracepoint specific and trace_unhandled hooks predate
the introduction of this dict, and do not receive it.
Add the aforementioned dict as an additional argument to the affected
handlers. To keep backwards compatibility (and avoid unnecessary work),
do not pass the dict if the number of arguments signals that handler
version predates this change.
perf script python: Allocate memory only if handler exists
Avoid allocating memory if hook handler is not available. This saves
unused memory allocation and simplifies error path.
Let handler in python_process_tracepoint point to either tracepoint
specific or trace_unhandled hook. Use dict to check if handler points to
trace_unhandled.
Remove the exit label in python_process_general_event and return when no
handler is available.
perf top: Support lookup of symbols in other mount namespaces.
The perf top command needs to unshare its fs from the helper threads in
order to successfully setns(2) during its symbol lookup. It also needs
to impelement a force flag to ignore ownership of perf-<pid>.map files.
perf jvmti: Fix linker error when libelf config is disabled
When libelf is disabled in the configuration, we get the following
linker error:
LINK libperf-jvmti.so
ld: cannot find -lelf
Makefile.perf:515: recipe for target 'libperf-jvmti.so' failed
Jiri pointed out that both librt and libelf are not really required. So
this patch fixes the linker error by getting rid of unwanted libraries
in the linker stage.
'perf annotate' was missing the handler for tracing data records.
Prior to this patch we obtained "unhandled" records when piping trace
events to perf annotate (using -D option to show the dump_printf
messages in process_event_synth_tracing_data_stub):
When converting from atomic_t to refcount_t we didn't follow the usual
step of initializing it to one before taking any new reference, which
trips over checking if taking a reference for a freed refcount_t, fix
it.
Brendan's report:
---
It's 4.12-rc7, with node v4.4.1. I'm building 4.13-rc1 now, as I hit
what I think is another unrelated perf bug and I'm starting to wonder
what else is broken on that version:
(root) /mnt/src/linux-4.12-rc7/tools/perf # ./perf record -F 99 -a -e
cpu-clock --cgroup=docker/f9e9d5df065b14646e8a11edc837a13877fd90c171137b2ba3feb67a0201cb65
-g
perf: /mnt/src/linux-4.12-rc7/tools/include/linux/refcount.h:108:
refcount_inc: Assertion `!(!refcount_inc_not_zero(r))' failed.
Aborted
Thomas Richter [Thu, 13 Jul 2017 13:02:52 +0000 (15:02 +0200)]
perf report: Fix kernel symbol adjustment for s390x
On s390x the kernel text segment starts at address 0x0. When perf
report reads kernel symbols from vmlinux file it adds an offset of
0x1000.
For example see symbol set_reset_devices:
[root@s8360047 linux-devel]# nm -A vmlinux| fgrep set_reset_devices
vmlinux:0000000001379000 t set_reset_devices
[root@s8360047 linux-devel]#
[root@s8360047 linux-devel]# fgrep set_reset_devices /proc/kallsyms 0000000001379000 t set_reset_devices
[root@s8360047 linux-devel]#
The kernel symbol table and the vmlinux file have the same address for
symbol set_reset_devices namely 1379000.
When perf report reads this symbols it displays it with address
symbol__new: set_reset_devices 0x137a000-0x137a018
There is a difference between perf report and vmlinux of 0x1000.
The reason for the difference is at kernel symbol load time in function
dso__load_sym(). The vmlinux file is investigated with its ELF header.
Command readelf shows this:
This leads to an invalid calculation of the symbol start address, see
file utit/symbol-elf.c line 974:
/* Adjust symbol to map to file offset */
if (adjust_kernel_syms)
sym.st_value -= shdr.sh_addr - shdr.sh_offset;
With shdr.sh_addr set to 0x0 and shdr.sh_offset set to 0x1000 as read
from the ELF .text section 0x1000 is added to the symbol address.
I would like to fix this by introducing an archticture specific function
named elf__needs_adjust_symbols(). This is the same approach as done by
PowerPC. The function currently does not exist for s390x and the
default weak one is used. The s390x specific one returns false when
symsrc_init() is invoked for kernel symbols and results in variable
adjust_kernel_syms being false. This omits the adjustment and the
correct address is displayed (when symbol resolvement does not work).
The s390x specific function returns false for kernel symbol adjustment
and returns true for kernel modules, processes and shared libraries.
Taeung had renamed it to total_samples, but using nr_samples, as in the
added explanation above, looks clearer and establishes the direct
connection, making clear it is about the _number_ of samples.
Taeung Song [Wed, 19 Jul 2017 21:36:45 +0000 (06:36 +0900)]
perf annotate: Introduce struct sym_hist_entry
struct sym_hist has addr[] but it should have not only number of samples
but also the sample period. So use new struct symhist_entry to pave the
way to have that.
Committer notes:
This initial patch will only introduce the struct sym_hist_entry and use
only the nr_samples member, which makes the code clearer and paves the
way to save the period as well.
tools lib: Update copy of strtobool from the kernel sources
Getting support for "on", "off" introduced in a81a5a17d44b ("lib: add
"on"/"off" support to kstrtobool") and making it check for NULL,
introduced in ef951599074b ("lib: move strtobool() to kstrtobool()").
Replacing prefixcmp(), same purpose, inverted result, so standardize on
the kernel variant, to reduce silly differences among tools/ and the
kernel sources, making it easier for people to work in both codebases.
perf trace: Filter out 'sshd' in the tracer ancestry in syswide tracing
Avoiding a loop, so now its quite convenient to ssh to a machine and
then simply do:
# perf trace
To trace all syscalls without causing a loop.
This was possible using --filter-pids, i.e. once you noticed the loop,
get the sshd pid and add it to --filter-pids, restarting the 'perf
trace'.
Now to figure out how to do that in a X terminal, the other common
scenario, which is way more involved, as there are multiple processes
communicating to process terminal activity...
Using --filter-pids + '-e \!syscall,names,you,dont,need' may be a good
approximation when having to do syswide tracing on your workstation.
No change in functionality, just to make clearer that what we want when
filtering the tracer pid in a system wide tracing session is to avoid a
feedback loop.
This also paves the way for a more interesting loop avoidance algorithm,
one that tries to figure out if we are in a ssh session, xterm, etc.
perf trace beauty clone: Suppress unused args according to 'flags' arg
The 'parent_tidptr', 'child_tidptr' and 'tls' arguments to the 'clone'
syscall are only used when certain flags are set in 'flags', suppress
them when those aren't there.
We'll also have to fix the argument ordering in different arches,
probably having multiple syscall_fmt entries with each possible order
and then use perf_evsel__env_arch() (if dealing with a perf.data file)
or the current system info, for live sessions.
perf trace: Allow specifying number of syscall args for tracepointless syscalls
When we don't have syscalls:sys_{enter,exit}_NAME, we had to resort to
dumping all the 6 syscall arguments, fix it by providing that info for
such syscalls, like 'clone'.
perf trace: Ditch __syscall__arg_val() variant, not needed anymore
All callers now can use syscall__arg_val(arg, idx), be it to iterate
thru the syscall arguments while taking into account alignment, or to
get values for other arguments that affect how the current argument
should be formatted (think of fcntl's 'cmd' and 'arg' arguments).
perf trace: Allow allocating sc->arg_fmt even without the syscall tracepoint
At least "clone" doesn't have (enter, exit) entries tracefs/events/syscalls/,
but we can provide a syscall_fmt and use it instead, as will be done for
"clone" in the next cset.
Kan Liang [Fri, 30 Jun 2017 14:16:56 +0000 (10:16 -0400)]
perf intel-pt: Always set no branch for dummy event
An earlier kernel patch allowed enabling PT and LBR at the same time on
Goldmont.
commit ccbebba4c6bf ("perf/x86/intel/pt: Bypass PT vs. LBR exclusivity
if the core supports it")
However, users still cannot use Intel PT and LBRs simultaneously. $
sudo perf record -e cycles,intel_pt//u -b -- sleep 1 Error: PMU
Hardware doesn't support sampling/overflow-interrupts.
PT implicitly adds dummy event in perf tool. dummy event is software
event which doesn't support LBR.
Always setting no branch for dummy event in Intel PT.
Kan Liang [Fri, 30 Jun 2017 14:16:55 +0000 (10:16 -0400)]
perf intel-pt: Set no_aux_samples for the tracking event
The reason of introducing the tracking event (a dummy software event) is
to collect side-band information. Additional sampling is wasteful.
no_aux_samples should be set for tracking event.
Merge tag 'perf-core-for-mingo-4.13-20170718' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
User visible changes:
- Initial support for namespaces, using setns to access files in
namespaces, grabbing their build-ids, etc. We still need to work
more to deal with namespaces that vanish before we can get the
needed data to do analysis, but this should be as good as what is
in bcc now (Krister Johansen)
- Add header record types to pipe-mode, now this command:
Will show the same as in non-pipe mode, i.e. involving a perf.data
file (David Carrillo-Cisneros)
- Implement a visual marker for fused x86 instructions in the annotate
TUI browser, available now in 'perf report', more work needed to have
it available as well in 'perf top' (Jin Yao)
- Beautify the fcntl syscall, which is an interesting one in the sense
that infrastructure had to be put in place to change the formatters of
some arguments according to the value in a previous one, i.e. cmd
dictates how arg and the syscall return will be formatted.
(Arnaldo Carvalho de Melo
Infrastructure changes:
- 'perf test attr' fixes (Jiri Olsa)
Vendor events changes:
- Add POWER9 PMU events Sukadev (Bhattiprolu)
- Support additional POWER8+ PVR in PMU mapfile (Shriya)
perf/core: Fix scheduling regression of pinned groups
Vince Weaver reported:
> I was tracking down some regressions in my perf_event_test testsuite.
> Some of the tests broke in the 4.11-rc1 timeframe.
>
> I've bisected one of them, this report is about
> tests/overflow/simul_oneshot_group_overflow
> This test creates an event group containing two sampling events, set
> to overflow to a signal handler (which disables and then refreshes the
> event).
>
> On a good kernel you get the following:
> Event perf::instructions with period 1000000
> Event perf::instructions with period 2000000
> fd 3 overflows: 946 (perf::instructions/1000000)
> fd 4 overflows: 473 (perf::instructions/2000000)
> Ending counts:
> Count 0: 946379875
> Count 1: 946365218
>
> With the broken kernels you get:
> Event perf::instructions with period 1000000
> Event perf::instructions with period 2000000
> fd 3 overflows: 938 (perf::instructions/1000000)
> fd 4 overflows: 318 (perf::instructions/2000000)
> Ending counts:
> Count 0: 946373080
> Count 1: 653373058
The root cause of the bug is that the following commit:
487f05e18a ("perf/core: Optimize event rescheduling on active contexts")
erronously assumed that event's 'pinned' setting determines whether the
event belongs to a pinned group or not, but in fact, it's the group
leader's pinned state that matters.
This was discovered by Vince in the test case described above, where two instruction
counters are grouped, the group leader is pinned, but the other event is not;
in the regressed case the counters were off by 33% (the difference between events'
periods), but should be the same within the error margin.
Fix the problem by looking at the group leader's pinning.
COND_FWD: conditional forward
COND_BWD: conditional backward
COND: conditional branch
UNCOND: unconditional branch
IND: indirect
CALL: function call
IND_CALL: indirect function call
RET: function return
SYSCALL: syscall
SYSRET: syscall return
COND_CALL: conditional function call
COND_RET: conditional function return
CROSS_4K and CROSS_2M:
They are the metrics checking for branches cross 4K or 2MB pages.
It's an approximate computing. We don't know if the area is 4K or
2MB, so always compute both.
To make the output simple, if a branch crosses 2M area, CROSS_4K
will not be incremented.
Change log
v7: Since the common branch type definitions are changed, some
tags/strings are updated accordingly.
v6: Remove branch_type_stat_display() since it's moved to branch.c.
v5: Remove the unnecessary sort__mode checking in
hist_iter__branch_callback().
v4: Comparing to previous version, the major changes are:
Add the computing of JCC forward/JCC backward and cross page checking
by using the from and to addresses.
Jin Yao [Tue, 18 Jul 2017 12:13:13 +0000 (20:13 +0800)]
perf util: Create branch.c/.h for common branch functions
Create new util/branch.c and util/branch.h to contain the common branch
functions. Such as:
branch_type_count(): Count the numbers of branch types
branch_type_name() : Return the name of branch type
branch_type_stat_display(): Display branch type statistics info
branch_type_str(): Construct the branch type string.
The branch type is saved in branch_flags.
Change log:
v8: Change PERF_BR_NONE to PERF_BR_UNKNOWN.
v7: Since the common branch type name is changed (e.g. JCC->COND),
this patch is performed the modification accordingly.
v6: Move that multiline conditional code inside {} brackets.
Move branch_type_stat_display() from builtin-report.c to
branch.c.
Move branch_type_str() from callchain.c to branch.c.
Jin Yao [Tue, 18 Jul 2017 12:13:10 +0000 (20:13 +0800)]
perf/x86/intel: Record branch type
Perf already has support for disassembling the branch instruction
and using the branch type for filtering. The patch just records
the branch type in perf_branch_entry.
Before recording, the patch converts the x86 branch type to
common branch type.
Change log:
v10: Set the branch_map array to be static. The previous version
has it on stack then makes the compiler to create it every
time when the function gets called.
v9: Use __ffs() to find first bit in type in common_branch_type().
It lets the code be clear.
v8: Change PERF_BR_NONE to PERF_BR_UNKNOWN.
v7: Just convert following x86 branch types to common branch types.
Jin Yao [Tue, 18 Jul 2017 12:13:09 +0000 (20:13 +0800)]
perf/core: Define the common branch type classification
It is often useful to know the branch types while analyzing branch data.
For example, a call is very different from a conditional branch.
Currently we have to look it up in binary while the binary may later not
be available and even the binary is available but user has to take some
time. It is very useful for user to check it directly in perf report.
Perf already has support for disassembling the branch instruction to get
the x86 branch type.
To keep consistent on kernel and userspace and make the classification
more common, the patch adds the common branch type classification
in perf_event.h.
The patch only defines a minimum but most common set of branch types.
PERF_BR_UNKNOWN : unknown
PERF_BR_COND ：conditional
PERF_BR_UNCOND : unconditional
PERF_BR_IND : indirect
PERF_BR_CALL : function call
PERF_BR_IND_CALL : indirect function call
PERF_BR_RET : function return
PERF_BR_SYSCALL : syscall
PERF_BR_SYSRET : syscall return
PERF_BR_COND_CALL : conditional function call
PERF_BR_COND_RET : conditional function return
The patch also adds a new field type (4 bits) in perf_branch_entry
to record the branch type.
Since the disassembling of branch instruction needs some overhead,
a new PERF_SAMPLE_BRANCH_TYPE_SAVE is introduced to indicate if it
needs to disassemble the branch instruction and record the branch
type.
Change log:
v10: Not changed.
v9: Not changed.
v8: Change PERF_BR_NONE to PERF_BR_UNKNOWN.
No other change.
v7: Just keep the most common branch types.
Others are removed.
v6: Not changed.
v5: Not changed. The v5 patch series just change the userspace.
v4: Comparing to previous version, the major changes are:
1. Remove the PERF_BR_JCC_FWD/PERF_BR_JCC_BWD, they will be
computed later in userspace.
2. Remove the "cross" field in perf_branch_entry. The cross page
computing will be done later in userspace.
There are three FEAT_OP* macros:
- FEAT_OPA: for features without process record.
- FEAT_OPP: for features with process record.
- FEAT_OPF: like FEAT_OPP but to show only if show_full_info flags
is set.
To add pipe-mode headers we need yet another variation of the macros
(one to specify whether a feature generates an auxiliar record).
Instead, we redefine macros so that:
- show_full_info is specified as an argument (to remove the
FEAT_OPF variation) and,
- it always sets "process" handler (to remove the FEAT_OPA variation).
Individual process handlers can be NULLed individually.
This allows to define two variations only:
- FEAT_OPR: synthesizes auxiliar event record.
- FEAT_OPN: doesn't synthesize an auxiliar event record.
Extend struct feat_fd to use a temporal buffer in pipe-mode, instead of
perf.data's file descriptor.
The header features build_id and aux_trace already have logic to print
in file-mode that heavily rely on lseek the file. For now, leave such
features inactive in pipe-mode and print a warning if their functions
are called in pipe-mode.
perf header: Don't pass struct perf_file_section to process_##_feat
struct perf_file_section is used in process_##_feat as container for
size and offset in the file descriptor. These attributes are meaninful
in pipe-mode but struct perf_file_section is not.
Add offset and size variables to struct feat_fd to store
perf_file_section's values in file-mode. Later on, the same variables
can be reused for pipe-mode.
Introduce struct feat_fd. This patch uses it as a wrapper around fd in
write_* functions for feature headers. Next patches will extend its
functionality to other feature header functions.
perf util: Add const modifier to buf in "writen" function
Make buf in helper function "writen" constant to simplify the life of
its callers.
This requires to hack a cast of buf prior to passing it to "ion" which
is simpler than the alternative of reworking the "ion" function to
provide a read and a write paths, the latter with constant buf argument.
Currently perf supports a mode to query inline stack. It works well for
finding user space inline functions but it doesn't work for kernel ones,
due to some unnecessary check.
This patch removes these unnecessary checks. Now kernel inline functions
can be reported.
Removing syscall_fmt::err_msg and instead always formatting negative
returns as errno values.
With this we can remove a lot of entries that have no special handling
besides the ones we can do by looking at the tracefs format files, i.e.
the types for the fields (e.g. pid_t), well known names (e.g. fd).
perf trace: Allow syscall arg formatters to request non suppression of zeros
The 'perf trace' tool is suppressing args set to zero, with the
exception of string tables (strarrays), which are kinda like enums, i.e.
we have maps to go from numbers to strings.
But the 'cmd' fcntl arg requires more specialized treatment, as its
value will regulate if the next fcntl syscall arg, 'arg', should be
ignored (not used) and also how to format the syscall return (fd, file
flags, etc), so add a 'show_zero" bool to struct syscall_arg_fmt, to
regulate this more explicitely.
Will be used in a following patch with fcntl, here is just the
mechanism.
perf trace: Group per syscall arg formatter info into one struct
Instead of having syscall_fmt.{arg_scnprintf,arg_parm}, introduce
struct syscall_arg_fmt and have these two, paving the way for more
state to change the formatting algorithms.
For instance, in the 'fcntl' 'cmd' case it is better not to suppress
it when being zero, showing instead its name "DUPFD".
We had that in an ad-hoc way just for strarrays, but with more involved
cases like fcntl, that can't be done with just a strarray, we'll need
a ".show_zero" arg in the 'cmd' syscall_arg_fmt.
Jiri Olsa [Mon, 3 Jul 2017 14:50:24 +0000 (16:50 +0200)]
perf tests attr: Add proper return values
The record command now properly returns the status of the tracee if
there's any. We need to properly set the expected return value of the
tracee in the attr tests.
Jiri Olsa [Mon, 3 Jul 2017 14:50:21 +0000 (16:50 +0200)]
perf tests attr: Add 1s for exclude_kernel and task base bits
There's an event open fallback which set exclude_kernel=1 in case use
does not have enough privileges. Adding both 0|1 for this attribute,
because we don't know what value it is.
Jiri Olsa [Mon, 3 Jul 2017 14:50:18 +0000 (16:50 +0200)]
perf tests attr: Add test_attr__ready function
We create many test events before the real ones just to test specific
features. But there's no way for attr tests to separate those test
events from those it needs to check.
Adding 'ready' call from the events open interface to trigger/start
events collection for attr test.
It can return NULL, in which case we should bail out and remove the
directory created with mkdtemp(), which is stored in the "__tempdir"
variable, not in "tempdir".
Cc: Masami Hiramatsu <[email protected]> Fixes: 8e5dc848356e ("perf test: Add a test case for SDT event") Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
perf record: Do not ask for precise_ip with --no-samples
When the user doesn't specify an event with -e/--event, 'perf record'
will use as a default the "cycles" event with the highest level of
precision in perf_event_attr.precise_ip, but --no-samples, if present,
is incompatible with precise_ip != 0, so use the newly introduced
__perf_event__add_default(precise = false) to fix that:
Before:
# perf record -n usleep 1
Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate.
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles:ppp).
/bin/dmesg may provide additional information.
No CONFIG_PERF_EVENTS=y kernel support configured?
#
After:
# perf record -n usleep 1
Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate.
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.018 MB perf.data ]
[root@jouet /]# perf evlist -v
cycles: size: 112, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
[root@jouet /]#
perf evlist: Allow asking for max precise_ip in add_default()
There are cases where we want to leave attr.precise_ip as zero, such
as when using 'perf record --no-samples', where this would make the
kernel return -EINVAL.
perf evsel: Allow asking for max precise_ip in new_cycles()
There are cases where we want to leave attr.precise_ip as zero, such
as when using 'perf record --no-samples', where this would make the
kernel return -EINVAL.
If a stripped binary is placed in the cache, the user is in a situation
where there's a cached elf file present, but it doesn't have any symtab
to use for name resolution. Grab the debuginfo for binaries that don't
end in .ko. This yields a better chance of resolving symbols from older
traces.
perf buildid-cache: Support binary objects from other namespaces
Teach buildid-cache how to add, remove, and update binary objects from
other mount namespaces. Allow probe events tracing binaries in
different namespaces to add their objects to the probe and build-id
caches too. As a handy side effect, this also lets us access SDT probes
in binaries from alternate mount namespaces.
perf probe: Allow placing uprobes in alternate namespaces.
Teaches perf how to place a uprobe on a file that's in a different mount
namespace. The user must add the probe using the --target-ns argument
to perf probe. Once it has been placed, it may be recorded against
without further namespace-specific commands.
perf maps: Lookup maps in both intitial mountns and inner mountns.
If a process is in a mountns and has symbols in /tmp/perf-<pid>.map,
look first in the namespace using the tgid for the pidns that the
process might be in. If the map isn't found there, try looking in the
mountns where perf is running, and use the tgid that's appropriate for
perf's pid namespace. If all else fails, use the original pid.
This allows us to locate a symbol map file in the mount namespace, if it
was generated there. However, we also try the tool's /tmp in case it's
there instead.
perf symbols: Find symbols in different mount namespace
Teach perf how to resolve symbols from binaries that are in a different
mount namespace from the tool. This allows perf to generate meaningful
stack traces even if the binary resides in a different mount namespace
from the tool.
In older distros we were not including our copies of unistd_{32,64}.h,
as we were relying on the system's asm/unistd.h, and a log time ago
the files to be included were asm-{x86_64,i386}/unistd.h.
Fix it by also carrying a copy of asm/unistd.h, that will be the same
as in modern distros and will allow us to provide missing __NR_setns,
for instance, in older distros.
projects / linux.git / log