- 21 Dec, 2011 11 commits
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Steven Rostedt authored
The function tracer is set up to allow any other subsystem (like perf) to use it. Ftrace already has a way to list what functions are enabled by the global_ops. It would be very helpful to let other users of the function tracer to be able to use the same code. Signed-off-by:Steven Rostedt <rostedt@goodmis.org>
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Steven Rostedt authored
There are two types of hashes in the ftrace_ops; one type is the filter_hash and the other is the notrace_hash. Either one may be null, meaning it has no elements. But when elements are added, the hash is allocated. Throughout the code, a check needs to be made to see if a hash exists or the hash has elements, but the check if the hash exists is usually missing causing the possible "NULL pointer dereference bug". Add a helper routine called "ftrace_hash_empty()" that returns true if the hash doesn't exist or its count is zero. As they mean the same thing. Last-bug-reported-by:
Jiri Olsa <jolsa@redhat.com> Signed-off-by:
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Steven Rostedt authored
When disabling the "notrace" records, that means we want to trace them. If the notrace_hash is zero, it means that we want to trace all records. But to disable a zero notrace_hash means nothing. The check for the notrace_hash count was incorrect with: if (hash && !hash->count) return With the correct comment above it that states that we do nothing if the notrace_hash has zero count. But !hash also means that the notrace hash has zero count. I think this was done to protect against dereferencing NULL. But if !hash is true, then we go through the following loop without doing a single thing. Fix it to: if (!hash || !hash->count) return; Signed-off-by: -
Steven Rostedt authored
Now that each set of pages in the function list are sorted by ip, we can use bsearch to find a record within each set of pages. This speeds up the ftrace_location() function by magnitudes. For archs (like x86) that need to add a breakpoint at every function that will be converted from a nop to a callback and vice versa, the breakpoint callback needs to know if the breakpoint was for ftrace or not. It requires finding the breakpoint ip within the records. Doing a linear search is extremely inefficient. It is a must to be able to do a fast binary search to find these locations. Signed-off-by: -
Steven Rostedt authored
Sort records by ip locations of the ftrace mcount calls on each of the set of pages in the function list. This helps in localizing cache usuage when updating the function locations, as well as gives us the ability to quickly find an ip location in the list. Signed-off-by: -
Steven Rostedt authored
As new functions come in to be initalized from mcount to nop, they are done by groups of pages. Whether it is the core kernel or a module. There's no need to keep track of these on a per record basis. At startup, and as any module is loaded, the functions to be traced are stored in a group of pages and added to the function list at the end. We just need to keep a pointer to the first page of the list that was added, and use that to know where to start on the list for initializing functions. Signed-off-by: -
Steven Rostedt authored
Allocate the mcount record pages as a group of pages as big as can be allocated and waste no more than a single page. Grouping the mcount pages as much as possible helps with cache locality, as we do not need to redirect with descriptors as we cross from page to page. It also allows us to do more with the records later on (sort them with bigger benefits). Signed-off-by: -
Steven Rostedt authored
Records that are added to the function trace table are permanently there, except for modules. By separating out the modules to their own pages that can be freed in one shot we can remove the "freed" flag and simplify some of the record management. Another benefit of doing this is that we can also move the records around; sort them. Signed-off-by: -
Steven Rostedt authored
The stop machine method to modify all functions in the kernel (some 20,000 of them) is the safest way to do so across all archs. But some archs may not need this big hammer approach to modify code on SMP machines, and can simply just update the code it needs. Adding a weak function arch_ftrace_update_code() that now does the stop machine, will also let any arch override this method. If the arch needs to check the system and then decide if it can avoid stop machine, it can still call ftrace_run_stop_machine() to use the old method. Signed-off-by: -
Steven Rostedt authored
When gcc inlines a function, it does not mark it with the mcount prologue, which in turn means that inlined functions are not traced by the function tracer. But if CONFIG_OPTIMIZE_INLINING is set, then gcc is allowed not to inline a function that is marked inline. Depending on the options and the compiler, a function may or may not be traced by the function tracer, depending on whether gcc decides to inline a function or not. This has caused several problems in the pass becaues gcc is not always consistent with what it decides to inline between different gcc versions. Some places should not be traced (like paravirt native_* functions) and these are mostly marked as inline. When gcc decides not to inline the function, and if that function should not be traced, then the ftrace function tracer will suddenly break when it use to work fine. This becomes even harder to debug when different versions of gcc will not inline that function, making the same kernel and config work for some gcc versions and not work for others. By making all functions marked inline to not be traced will remove the ambiguity that gcc adds when it comes to tracing functions marked inline. All gcc versions will be consistent with what functions are traced and having volatile working code will be removed. Note, only the inline macro when CONFIG_OPTIMIZE_INLINING is set needs to have notrace added, as the attribute __always_inline will force the function to be inlined and then not traced. Signed-off-by: -
Jiri Olsa authored
Multiple users of the function tracer can register their functions with the ftrace_ops structure. The accounting within ftrace will update the counter on each function record that is being traced. When the ftrace_ops filtering adds or removes functions, the function records will be updated accordingly if the ftrace_ops is still registered. When a ftrace_ops is removed, the counter of the function records, that the ftrace_ops traces, are decremented. When they reach zero the functions that they represent are modified to stop calling the mcount code. When changes are made, the code is updated via stop_machine() with a command passed to the function to tell it what to do. There is an ENABLE and DISABLE command that tells the called function to enable or disable the functions. But the ENABLE is really a misnomer as it should just update the records, as records that have been enabled and now have a count of zero should be disabled. The DISABLE command is used to disable all functions regardless of their counter values. This is the big off switch and is not the complement of the ENABLE command. To make matters worse, when a ftrace_ops is unregistered and there is another ftrace_ops registered, neither the DISABLE nor the ENABLE command are set when calling into the stop_machine() function and the records will not be updated to match their counter. A command is passed to that function that will update the mcount code to call the registered callback directly if it is the only one left. This means that the ftrace_ops that is still registered will have its callback called by all functions that have been set for it as well as the ftrace_ops that was just unregistered. Here's a way to trigger this bug. Compile the kernel with CONFIG_FUNCTION_PROFILER set and with CONFIG_FUNCTION_GRAPH not set: CONFIG_FUNCTION_PROFILER=y # CONFIG_FUNCTION_GRAPH is not set This will force the function profiler to use the function tracer instead of the function graph tracer. # cd /sys/kernel/debug/tracing # echo schedule > set_ftrace_filter # echo function > current_tracer # cat set_ftrace_filter schedule # cat trace # tracer: nop # # entries-in-buffer/entries-written: 692/68108025 #P:4 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | kworker/0:2-909 [000] .... 531.235574: schedule <-worker_thread <idle>-0 [001] .N.. 531.235575: schedule <-cpu_idle kworker/0:2-909 [000] .... 531.235597: schedule <-worker_thread sshd-2563 [001] .... 531.235647: schedule <-schedule_hrtimeout_range_clock # echo 1 > function_profile_enabled # echo 0 > function_porfile_enabled # cat set_ftrace_filter schedule # cat trace # tracer: function # # entries-in-buffer/entries-written: 159701/118821262 #P:4 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [002] ...1 604.870655: local_touch_nmi <-cpu_idle <idle>-0 [002] d..1 604.870655: enter_idle <-cpu_idle <idle>-0 [002] d..1 604.870656: atomic_notifier_call_chain <-enter_idle <idle>-0 [002] d..1 604.870656: __atomic_notifier_call_chain <-atomic_notifier_call_chain The same problem could have happened with the trace_probe_ops, but they are modified with the set_frace_filter file which does the update at closure of the file. The simple solution is to change ENABLE to UPDATE and call it every time an ftrace_ops is unregistered. Link: http://lkml.kernel.org/r/1323105776-26961-3-git-send-email-jolsa@redhat.com Cc: stable@vger.kernel.org # 3.0+ Signed-off-by:
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- 12 Dec, 2011 3 commits
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Andrew Vagin authored
It's the counterpart of perf_session__parse_sample. v2: fixed mistakes found by David Ahern. v3: s/data/sample/ s/perf_event__change_sample/perf_event__synthesize_sample Reviewed-by:David Ahern <dsahern@gmail.com> Cc: Arun Sharma <asharma@fb.com> Cc: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: devel@openvz.org Link: http://lkml.kernel.org/r/1323266161-394927-3-git-send-email-avagin@openvz.orgSigned-off-by:
Andrew Vagin <avagin@openvz.org> Signed-off-by:
Arnaldo Carvalho de Melo <acme@redhat.com>
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Robert Richter authored
The option is documented in man perf-script but was not yet implemented: -a Force system-wide collection. Scripts run without a <command> normally use -a by default, while scripts run with a <command> normally don't - this option allows the latter to be run in system-wide mode. As with perf record you now can profile in system-wide mode for the runtime of a given command, e.g.: # perf script -a syscall-counts sleep 2 Cc: Ingo Molnar <mingo@elte.hu> Link: http://lkml.kernel.org/r/1322229925-10075-1-git-send-email-robert.richter@amd.comSigned-off-by:Robert Richter <robert.richter@amd.com> Signed-off-by:
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Robert Richter authored
Fix mem leaks and missing NULL pointer checks after strdup(). And get_script_path() did not free __script_root in case of continue. Introduce a helper function get_script_root(). Cc: Ingo Molnar <mingo@elte.hu> Link: http://lkml.kernel.org/r/1322217520-3287-1-git-send-email-robert.richter@amd.comSigned-off-by:
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- 06 Dec, 2011 14 commits
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Gleb Natapov authored
KVM needs to know perf capability to decide which PMU it can expose to a guest. Signed-off-by:
Gleb Natapov <gleb@redhat.com> Signed-off-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1320929850-10480-8-git-send-email-gleb@redhat.comSigned-off-by:
Ingo Molnar <mingo@elte.hu>
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Peter Zijlstra authored
Implement the disabling of arch events as a quirk so that we can print a message along with it. This creates some visibility into the problem space and could allow us to work on adding more work-around like the AAJ80 one. Requested-by:
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Gleb Natapov authored
Intel CPUs report non-available architectural events in cpuid leaf 0AH.EBX. Use it to disable events that are not available according to CPU. Signed-off-by:
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Peter Zijlstra authored
Provide two initializers for jump_label_key that initialize it enabled or disabled. Also modify all jump_label code to allow for jump_labels to be initialized enabled. Signed-off-by:
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Peter Zijlstra authored
WARNING: arch/x86/kernel/built-in.o(.text+0x4c71): Section mismatch in reference from the function arch_jump_label_transform_static() to the function .init.text:text_poke_early() The function arch_jump_label_transform_static() references the function __init text_poke_early(). This is often because arch_jump_label_transform_static lacks a __init annotation or the annotation of text_poke_early is wrong. Signed-off-by:
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Ingo Molnar authored
Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core
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Gleb Natapov authored
jump_lable patching is very expensive operation that involves pausing all cpus. The patching of perf_sched_events jump_label is easily controllable from userspace by unprivileged user. When te user runs a loop like this: "while true; do perf stat -e cycles true; done" ... the performance of my test application that just increments a counter for one second drops by 4%. This is on a 16 cpu box with my test application using only one of them. An impact on a real server doing real work will be worse. Performance of KVM PMU drops nearly 50% due to jump_lable for "perf record" since KVM PMU implementation creates and destroys perf event frequently. This patch introduces a way to rate limit jump_label patching and uses it to fix the above problem. I believe that as jump_label use will spread the problem will become more common and thus solving it in a generic code is appropriate. Also fixing it in the perf code would result in moving jump_label accounting logic to perf code with all the ifdefs in case of JUMP_LABEL=n kernel. With this patch all details are nicely hidden inside jump_label code. Signed-off-by:
Jason Baron <jbaron@redhat.com> Signed-off-by:
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Peter Zijlstra authored
Deng-Cheng Zhu reported that sibling events that were created disabled with enable_on_exec would never get enabled. Iterate all events instead of the group lists. Reported-by:
Deng-Cheng Zhu <dczhu@mips.com> Tested-by:
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Peter Zijlstra authored
Signed-off-by:
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Peter Zijlstra authored
This avoids a scheduling failure for cases like: cycles, cycles, instructions, instructions (on Core2) Which would end up being programmed like: PMC0, PMC1, FP-instructions, fail Because all events will have the same weight. Signed-off-by:
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Robert Richter authored
The current x86 event scheduler fails to resolve scheduling problems of certain combinations of events and constraints. This happens if the counter mask of such an event is not a subset of any other counter mask of a constraint with an equal or higher weight, e.g. constraints of the AMD family 15h pmu: counter mask weight amd_f15_PMC30 0x09 2 <--- overlapping counters amd_f15_PMC20 0x07 3 amd_f15_PMC53 0x38 3 The scheduler does not find then an existing solution. Here is an example: event code counter failure possible solution 0x02E PMC[3,0] 0 3 0x043 PMC[2:0] 1 0 0x045 PMC[2:0] 2 1 0x046 PMC[2:0] FAIL 2 The event scheduler may not select the correct counter in the first cycle because it needs to know which subsequent events will be scheduled. It may fail to schedule the events then. To solve this, we now save the scheduler state of events with overlapping counter counstraints. If we fail to schedule the events we rollback to those states and try to use another free counter. Constraints with overlapping counters are marked with a new introduced overlap flag. We set the overlap flag for such constraints to give the scheduler a hint which events to select for counter rescheduling. The EVENT_CONSTRAINT_OVERLAP() macro can be used for this. Care must be taken as the rescheduling algorithm is O(n!) which will increase scheduling cycles for an over-commited system dramatically. The number of such EVENT_CONSTRAINT_OVERLAP() macros and its counter masks must be kept at a minimum. Thus, the current stack is limited to 2 states to limit the number of loops the algorithm takes in the worst case. On systems with no overlapping-counter constraints, this implementation does not increase the loop count compared to the previous algorithm. V2: * Renamed redo -> overlap. * Reimplementation using perf scheduling helper functions. V3: * Added WARN_ON_ONCE() if out of save states. * Changed function interface of perf_sched_restore_state() to use bool as return value. Signed-off-by: -
Robert Richter authored
This patch introduces x86 perf scheduler code helper functions. We need this to later add more complex functionality to support overlapping counter constraints (next patch). The algorithm is modified so that the range of weight values is now generated from the constraints. There shouldn't be other functional changes. With the helper functions the scheduler is controlled. There are functions to initialize, traverse the event list, find unused counters etc. The scheduler keeps its own state. V3: * Added macro for_each_set_bit_cont(). * Changed functions interfaces of perf_sched_find_counter() and perf_sched_next_event() to use bool as return value. * Added some comments to make code better understandable. V4: * Fix broken event assignment if weight of the first event is not wmin (perf_sched_init()). Signed-off-by:
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Peter Zijlstra authored
Gleb writes: > Currently pmu is disabled and re-enabled on each timer interrupt even > when no rotation or frequency adjustment is needed. On Intel CPU this > results in two writes into PERF_GLOBAL_CTRL MSR per tick. On bare metal > it does not cause significant slowdown, but when running perf in a virtual > machine it leads to 20% slowdown on my machine. Cure this by keeping a perf_event_context::nr_freq counter that counts the number of active events that require frequency adjustments and use this in a similar fashion to the already existing nr_events != nr_active test in perf_rotate_context(). By being able to exclude both rotation and frequency adjustments a-priory for the common case we can avoid the otherwise superfluous PMU disable. Suggested-by:
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Ingo Molnar authored
Merge reason: Add these cherry-picked commits so that future changes on perf/core don't conflict. Signed-off-by:
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- 05 Dec, 2011 12 commits
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Steven Rostedt authored
If the set_ftrace_filter is cleared by writing just whitespace to it, then the filter hash refcounts will be decremented but not updated. This causes two bugs: 1) No functions will be enabled for tracing when they all should be 2) If the users clears the set_ftrace_filter twice, it will crash ftrace: ------------[ cut here ]------------ WARNING: at /home/rostedt/work/git/linux-trace.git/kernel/trace/ftrace.c:1384 __ftrace_hash_rec_update.part.27+0x157/0x1a7() Modules linked in: Pid: 2330, comm: bash Not tainted 3.1.0-test+ #32 Call Trace: [<ffffffff81051828>] warn_slowpath_common+0x83/0x9b [<ffffffff8105185a>] warn_slowpath_null+0x1a/0x1c [<ffffffff810ba362>] __ftrace_hash_rec_update.part.27+0x157/0x1a7 [<ffffffff810ba6e8>] ? ftrace_regex_release+0xa7/0x10f [<ffffffff8111bdfe>] ? kfree+0xe5/0x115 [<ffffffff810ba51e>] ftrace_hash_move+0x2e/0x151 [<ffffffff810ba6fb>] ftrace_regex_release+0xba/0x10f [<ffffffff8112e49a>] fput+0xfd/0x1c2 [<ffffffff8112b54c>] filp_close+0x6d/0x78 [<ffffffff8113a92d>] sys_dup3+0x197/0x1c1 [<ffffffff8113a9a6>] sys_dup2+0x4f/0x54 [<ffffffff8150cac2>] system_call_fastpath+0x16/0x1b ---[ end trace 77a3a7ee73794a02 ]--- Link: http://lkml.kernel.org/r/20111101141420.GA4918@debianReported-by:
Rabin Vincent <rabin@rab.in> Signed-off-by:
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Steven Rostedt authored
A update is made to the sched:sched_switch event that adds some logic to the first parameter of the __print_flags() that shows the state of tasks. This change cause perf to fail parsing the flags. A simple fix is needed to have the parser be able to process ops within the argument. Cc: stable@vger.kernel.org Reported-by:
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Gleb Natapov authored
If cpu A calls jump_label_inc() just after atomic_add_return() is called by cpu B, atomic_inc_not_zero() will return value greater then zero and jump_label_inc() will return to a caller before jump_label_update() finishes its job on cpu B. Link: http://lkml.kernel.org/r/20111018175551.GH17571@redhat.com Cc: stable@vger.kernel.org Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by:
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Steven Rostedt authored
A forced undef of a config value was used for testing and was accidently left in during the final commit. This causes x86 to run slower than needed while running function tracing as well as causes the function graph selftest to fail when DYNMAIC_FTRACE is not set. This is because the code in MCOUNT expects the ftrace code to be processed with the config value set that happened to be forced not set. The forced config option was left in by: commit 6331c28c ftrace: Fix dynamic selftest failure on some archs Link: http://lkml.kernel.org/r/20111102150255.GA6973@debian Cc: stable@vger.kernel.org Reported-by: -
Li Zefan authored
Though not all events have field 'prev_pid', it was allowed to do this: # echo 'prev_pid == 100' > events/sched/filter but commit 75b8e982 (tracing/filter: Swap entire filter of events) broke it without any reason. Link: http://lkml.kernel.org/r/4EAF46CF.8040408@cn.fujitsu.comSigned-off-by:
Li Zefan <lizf@cn.fujitsu.com> Signed-off-by:
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Ilya Dryomov authored
Fix a bug introduced by e9dbfae5, which prevents event_subsystem from ever being released. Ref_count was added to keep track of subsystem users, not for counting events. Subsystem is created with ref_count = 1, so there is no need to increment it for every event, we have nr_events for that. Fix this by touching ref_count only when we actually have a new user - subsystem_open(). Cc: stable@vger.kernel.org Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Link: http://lkml.kernel.org/r/1320052062-7846-1-git-send-email-idryomov@gmail.comSigned-off-by:
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Masami Hiramatsu authored
Add instruction dump mode to insn_sanity tool for checking decoder really decoded instructions. This mode is enabled when passing double -v (-vv) to insn_sanity. It is useful for who wants to check whether the decoder can decode some instructions correctly. e.g. $ echo 0f 73 10 11 | ./insn_sanity -y -vv -i - Instruction = { .prefixes = { .value = 0, bytes[] = {0, 0, 0, 0}, .got = 1, .nbytes = 0}, .rex_prefix = { .value = 0, bytes[] = {0, 0, 0, 0}, .got = 1, .nbytes = 0}, .vex_prefix = { .value = 0, bytes[] = {0, 0, 0, 0}, .got = 1, .nbytes = 0}, .opcode = { .value = 29455, bytes[] = {f, 73, 0, 0}, .got = 1, .nbytes = 2}, .modrm = { .value = 16, bytes[] = {10, 0, 0, 0}, .got = 1, .nbytes = 1}, .sib = { .value = 0, bytes[] = {0, 0, 0, 0}, .got = 1, .nbytes = 0}, .displacement = { .value = 0, bytes[] = {0, 0, 0, 0}, .got = 1, .nbytes = 0}, .immediate1 = { .value = 17, bytes[] = {11, 0, 0, 0}, .got = 1, .nbytes = 1}, .immediate2 = { .value = 0, bytes[] = {0, 0, 0, 0}, .got = 0, .nbytes = 0}, .attr = 44800, .opnd_bytes = 4, .addr_bytes = 8, .length = 4, .x86_64 = 1, .kaddr = 0x7fff0f7d9430} Success: decoded and checked 1 given instructions with 0 errors (seed:0x0) Signed-off-by:Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20111205120603.15475.91192.stgit@cloudSigned-off-by:
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Masami Hiramatsu authored
Since new Intel software developers manual introduces new format for AVX instruction set (including AVX2), it is important to update x86-opcode-map.txt to fit those changes. Signed-off-by:
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Masami Hiramatsu authored
Fix x86 instruction decoder test to dump all error messages to stderr and others to stdout. Signed-off-by:
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Masami Hiramatsu authored
Fix instruction decoder test (insn_sanity), so that it doesn't show both info and error messages twice on same instruction. (In that case, show only error message) Signed-off-by:
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Masami Hiramatsu authored
For reducing memory usage of attribute table, x86 instruction decoder puts "Group" attribute only on "no-last-prefix" attribute table (same as vex_p == 0 case). Thus, the decoder should look no-last-prefix table first, and then only if it is not a group, move on to "with-last-prefix" table (vex_p != 0). However, current implementation, inat_get_avx_attribute() looks with-last-prefix directly. So, when decoding a grouped AVX instruction, the decoder fails to find correct group because there is no "Group" attribute on the table. This ends up with the mis-decoding of instructions, as Ingo reported in http://thread.gmane.org/gmane.linux.kernel/1214103 This patch fixes it to check no-last-prefix table first even if that is an AVX instruction, and get an attribute from "with last-prefix" table only if that is not a group. Reported-by:
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Masami Hiramatsu authored
Fix arch/x86/tools/Makefile to compile both test tools correctly. This bug leads build error. Signed-off-by:
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