Introduce x86 arch-specific optimization code, which supports
both of x86-32 and x86-64.
This code also supports safety checking, which decodes whole of
a function in which probe is inserted, and checks following
conditions before optimization:
- The optimized instructions which will be replaced by a jump instruction
don't straddle the function boundary.
- There is no indirect jump instruction, because it will jumps into
the address range which is replaced by jump operand.
- There is no jump/loop instruction which jumps into the address range
which is replaced by jump operand.
- Don't optimize kprobes if it is in functions into which fixup code will
jumps.
This uses text_poke_multibyte() which doesn't support modifying
code on NMI/MCE handler. However, since kprobes itself doesn't
support NMI/MCE code probing, it's not a problem.
Changes in v9:
- Use *_text_reserved() for checking the probe can be optimized.
- Verify jump address range is in 2G range when preparing slot.
- Backup original code when switching optimized buffer, instead of
preparing buffer, because there can be int3 of other probes in
preparing phase.
- Check kprobe is disabled in arch_check_optimized_kprobe().
- Strictly check indirect jump opcodes (ff /4, ff /5).
Changes in v6:
- Split stop_machine-based jump patching code.
- Update comments and coding style.
Changes in v5:
- Introduce stop_machine-based jump replacing.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133446.6725.78994.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Introduce kprobes jump optimization arch-independent parts.
Kprobes uses breakpoint instruction for interrupting execution
flow, on some architectures, it can be replaced by a jump
instruction and interruption emulation code. This gains kprobs'
performance drastically.
To enable this feature, set CONFIG_OPTPROBES=y (default y if the
arch supports OPTPROBE).
Changes in v9:
- Fix a bug to optimize probe when enabling.
- Check nearby probes can be optimize/unoptimize when disarming/arming
kprobes, instead of registering/unregistering. This will help
kprobe-tracer because most of probes on it are usually disabled.
Changes in v6:
- Cleanup coding style for readability.
- Add comments around get/put_online_cpus().
Changes in v5:
- Use get_online_cpus()/put_online_cpus() for avoiding text_mutex
deadlock.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Be more clear about DSO long names and tell from which file
kernel symbols were obtained, all in --verbose mode:
[root@mica ~]# perf report -v > /dev/null
Looking at the vmlinux_path (5 entries long)
Using /lib/modules/2.6.33-rc8-tip-00777-g0918527-dirty/build/vmlinux for symbols
[root@mica ~]# mv /lib/modules/2.6.33-rc8-tip-00777-g0918527-dirty/build/vmlinux /tmp/dd
[root@mica ~]# perf report -v > /dev/null
Looking at the vmlinux_path (5 entries long)
Using /proc/kallsyms for symbols
[root@mica ~]#
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1266866139-6361-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
syscall_name() helper, which resolves a syscall arch number to
its name, is not yet available as we first need to implement
event injection for it to work.
Remove it from the documentation or tag its references as
unavailable yet. Once it's implemented, we can just revert
the current patch.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Keiichi KII <k-keiichi@bx.jp.nec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
The check-perf-trace script only checks Perl functionality, and
doesn't really need to be listed as as user script anyway.
This only removes the '-report' shell script, so although it doesn't
appear in the listing, the '-record' shell script and the check perf
trace perl script itself is still available and can still be run
manually as such:
$ libexec/perf-core/scripts/perl/bin/check-perf-trace-record
$ perf trace -s libexec/perf-core/scripts/perl/check-perf-trace.pl
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Keiichi KII <k-keiichi@bx.jp.nec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <1264580883-15324-6-git-send-email-tzanussi@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
As the parent comm then is worthless, confusing users about the
thread where the sample really happened, leading to think that
the sample happened in the parent, not where it really happened,
in the children of a thread for which a PERF_RECORD_COMM event
was not received.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1266627727-19715-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When 'perf record -g' a existing process, even with debuginfo
packages, still cannnot get symbol from 'perf report'.
try:
perf record -g -p `pidof xxx` -f
perf report
68.26% :1181 b74870f2 [.] 0x000000b74870f2
|
|--32.09%-- 0xb73b5b44
| 0xb7487102
| 0xb748a4e2
| 0xb748633d
| 0xb73b41cd
| 0xb73b4467
| 0xb747d531
The reason is: for existing process, in __cmd_record(),
the pid is 0 rather than the existing process id.
Signed-off-by: Austin Zhang <austin_zhang@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4710.10.255.24.35.1265389362.squirrel@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fixes these warnings:
arch/x86/kernel/alternative.c: In function 'alternatives_text_reserved':
arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:402: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
arch/x86/kernel/alternative.c:405: warning: comparison of distinct pointer types lacks a cast
Caused by:
2cfa197: ftrace/alternatives: Introducing *_text_reserved functions
Changes in v2:
- Use local variables to compare, instead of type casts.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20100205171647.15750.37221.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Because we may have aliases, like __GI___strcoll_l in
/lib64/libc-2.10.2.so that appears in objdump as:
$ objdump --start-address=0x0000003715a86420 \
--stop-address=0x0000003715a872dc -dS /lib64/libc-2.10.2.so
0000003715a86420 <__strcoll_l>:
3715a86420: 55 push %rbp
3715a86421: 48 89 e5 mov %rsp,%rbp
3715a86424: 41 57 push %r15
[root@doppio linux-2.6-tip]#
So look for the address exactly at the start of the line instead
so that annotation can work for in these cases.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Kirill Smelkov <kirr@landau.phys.spbu.ru>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1265550376-12665-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
First, for programs and prelinked libraries, annotate code was
fooled by objdump output IPs (src->eip in the code) being
wrongly converted to absolute IPs. In such case there were no
conversion needed, but in
src->eip = strtoull(src->line, NULL, 16);
src->eip = map->unmap_ip(map, src->eip); // = eip + map->start - map->pgoff
we were reading absolute address from objdump (e.g. 8048604) and
then almost doubling it, because eip & map->start are
approximately close for small programs.
Needless to say, that later, in record_precise_ip() there was no
matching with real runtime IPs.
And second, like with `perf annotate` the problem with
non-prelinked *.so was that we were doing rip -> objdump address
conversion wrong.
Also, because unlike `perf annotate`, `perf top` code does
annotation based on absolute IPs for performance reasons(*), new
helper for mapping objdump addresse to IP is introduced.
(*) we get samples info in absolute IPs, and since we do lots of
hit-testing on absolute IPs at runtime in record_precise_ip(), it's
better to convert objdump addresses to IPs once and do no conversion
at runtime.
I also had to fix how objdump output is parsed (with hardcoded
8/16 characters format, which was inappropriate for ET_DYN dsos
with small addresses like '4ac')
Also note, that not all objdump output lines has associtated
IPs, e.g. look at source lines here:
000004ac <my_strlen>:
extern "C"
int my_strlen(const char *s)
4ac: 55 push %ebp
4ad: 89 e5 mov %esp,%ebp
4af: 83 ec 10 sub $0x10,%esp
{
int len = 0;
4b2: c7 45 fc 00 00 00 00 movl $0x0,-0x4(%ebp)
4b9: eb 08 jmp 4c3 <my_strlen+0x17>
while (*s) {
++len;
4bb: 83 45 fc 01 addl $0x1,-0x4(%ebp)
++s;
4bf: 83 45 08 01 addl $0x1,0x8(%ebp)
So we mark them with eip=0, and ignore such lines in annotate
lookup code.
Signed-off-by: Kirill Smelkov <kirr@landau.phys.spbu.ru>
[ Note: one hunk of this patch was applied by Mike in 57d8188 ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1265550376-12665-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We cannot assume that because hwc->idx == assign[i], we can avoid
reprogramming the counter in hw_perf_enable().
The event may have been scheduled out and another event may have been
programmed into this counter. Thus, we need a more robust way of
verifying if the counter still contains config/data related to an event.
This patch adds a generation number to each counter on each cpu. Using
this mechanism we can verify reliabilty whether the content of a counter
corresponds to an event.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4b66dc67.0b38560a.1635.ffffae18@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Pretty much all of the calls do perf_disable/perf_enable cycles, pull
that out to cut back on hardware programming.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
By relying on logic in dso__load_kernel_sym(), we can
automatically load vmlinux.
The only thing which needs to be adjusted, is how --sym-annotate
option is handled - now we can't rely on vmlinux been loaded
until full successful pass of dso__load_vmlinux(), but that's
not the case if we'll do sym_filter_entry setup in
symbol_filter().
So move this step right after event__process_sample() where we
know the whole dso__load_kernel_sym() pass is done.
By the way, though conceptually similar `perf top` still can't
annotate userspace - see next patches with fixes.
Signed-off-by: Kirill Smelkov <kirr@landau.phys.spbu.ru>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1265223128-11786-9-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
