hw_breakpoint creation needs to account stuff per-task to ensure there
is always sufficient hardware resources to back these things due to
ptrace.
With the perf per pmu context changes the event initialization no
longer has access to the event context, for the simple reason that we
need to first find the pmu (result of initialization) before we can
find the context.
This makes hw_breakpoints unhappy, because it can no longer do per
task accounting, cure this by frobbing a task pointer in the event::hw
bits for now...
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20101014203625.391543667@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
So that we can pass the task pointer to the event allocation, so that
we can use task associated data during event initialization.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101014203625.340789919@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently it looks like find_lively_task_by_vpid() takes a task ref
and relies on find_get_context() to drop it.
The problem is that perf_event_create_kernel_counter() shouldn't be
dropping task refs.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Matt Helsley <matthltc@us.ibm.com>
LKML-Reference: <20101014203625.278436085@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Matt found we trigger the WARN_ON_ONCE() in perf_group_attach() when we take
the move_group path in perf_event_open().
Since we cannot de-construct the group (we rely on it to move the events), we
have to simply ignore the double attach. The group state is context invariant
and doesn't need changing.
Reported-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1287135757.29097.1368.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.
Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.
The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.
Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The group_sched_in() function uses a transactional approach to schedule
a group of events. In a group, either all events can be scheduled or
none are. To schedule each event in, the function calls event_sched_in().
In case of error, event_sched_out() is called on each event in the group.
The problem is that event_sched_out() does not completely cancel the
effects of event_sched_in(). Furthermore event_sched_out() changes the
state of the event as if it had run which is not true is this particular
case.
Those inconsistencies impact time tracking fields and may lead to events
in a group not all reporting the same time_enabled and time_running values.
This is demonstrated with the example below:
$ task -eunhalted_core_cycles,baclears,baclears -e unhalted_core_cycles,baclears,baclears sleep 5
1946101 unhalted_core_cycles (32.85% scaling, ena=829181, run=556827)
11423 baclears (32.85% scaling, ena=829181, run=556827)
7671 baclears (0.00% scaling, ena=556827, run=556827)
2250443 unhalted_core_cycles (57.83% scaling, ena=962822, run=405995)
11705 baclears (57.83% scaling, ena=962822, run=405995)
11705 baclears (57.83% scaling, ena=962822, run=405995)
Notice that in the first group, the last baclears event does not
report the same timings as its siblings.
This issue comes from the fact that tstamp_stopped is updated
by event_sched_out() as if the event had actually run.
To solve the issue, we must ensure that, in case of error, there is
no change in the event state whatsoever. That means timings must
remain as they were when entering group_sched_in().
To do this we defer updating tstamp_running until we know the
transaction succeeded. Therefore, we have split event_sched_in()
in two parts separating the update to tstamp_running.
Similarly, in case of error, we do not want to update tstamp_stopped.
Therefore, we have split event_sched_out() in two parts separating
the update to tstamp_stopped.
With this patch, we now get the following output:
$ task -eunhalted_core_cycles,baclears,baclears -e unhalted_core_cycles,baclears,baclears sleep 5
2492050 unhalted_core_cycles (71.75% scaling, ena=1093330, run=308841)
11243 baclears (71.75% scaling, ena=1093330, run=308841)
11243 baclears (71.75% scaling, ena=1093330, run=308841)
1852746 unhalted_core_cycles (0.00% scaling, ena=784489, run=784489)
9253 baclears (0.00% scaling, ena=784489, run=784489)
9253 baclears (0.00% scaling, ena=784489, run=784489)
Note that the uneven timing between groups is a side effect of
the process spending most of its time sleeping, i.e., not enough
event rotations (but that's a separate issue).
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4cb86b4c.41e9d80a.44e9.3e19@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
PERF_COUNT_HW_CACHE_DTLB:READ:MISS had a bogus umask value of 0 which
counts nothing. Needed to be 0x7 (to count all possibilities).
PERF_COUNT_HW_CACHE_ITLB:READ:MISS had a bogus umask value of 0 which
counts nothing. Needed to be 0x3 (to count all possibilities).
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: <stable@kernel.org> # as far back as it applies
LKML-Reference: <4cb85478.41e9d80a.44e2.3f00@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
You can only call update_context_time() when the context
is active, i.e., the thread it is attached to is still running.
However, perf_event_read() can be called even when the context
is inactive, e.g., user read() the counters. The call to
update_context_time() must be conditioned on the status of
the context, otherwise, bogus time_enabled, time_running may
be returned. Here is an example on AMD64. The task program
is an example from libpfm4. The -p prints deltas every 1s.
$ task -p -e cpu_clk_unhalted sleep 5
2,266,610 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
0 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
0 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
0 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
0 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
5,242,358,071 cpu_clk_unhalted (99.95% scaling, ena=5,000,359,984, run=2,319,270)
Whereas if you don't read deltas, e.g., no call to perf_event_read() until
the process terminates:
$ task -e cpu_clk_unhalted sleep 5
2,497,783 cpu_clk_unhalted (0.00% scaling, ena=2,376,899, run=2,376,899)
Notice that time_enable, time_running are bogus in the first example
causing bogus scaling.
This patch fixes the problem, by conditionally calling update_context_time()
in perf_event_read().
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org
LKML-Reference: <4cb856dc.51edd80a.5ae0.38fb@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Even though the parent is recorded with the normal function tracing
of the latency tracers (irqsoff and wakeup), the function graph
recording is bogus.
This is due to the function graph messing with the return stack.
The latency tracers pass in as the parent CALLER_ADDR0, which
works fine for plain function tracing. But this causes bogus output
with the graph tracer:
3) <idle>-0 | d.s3. 0.000 us | return_to_handler();
3) <idle>-0 | d.s3. 0.000 us | _raw_spin_unlock_irqrestore();
3) <idle>-0 | d.s3. 0.000 us | return_to_handler();
3) <idle>-0 | d.s3. 0.000 us | trace_hardirqs_on();
The "return_to_handle()" call is the trampoline of the
function graph tracer, and is meaningless in this context.
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The preempt and irqsoff tracers have three types of function tracers.
Normal function tracer, function graph entry, and function graph return.
Each of these use a complex dance to prevent recursion and whether
to trace the data or not (depending if interrupts are enabled or not).
This patch moves the duplicate code into a single routine, to
prevent future mistakes with modifying duplicate complex code.
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The wakeup tracer has three types of function tracers. Normal
function tracer, function graph entry, and function graph return.
Each of these use a complex dance to prevent recursion and whether
to trace the data or not (depending on the wake_task variable).
This patch moves the duplicate code into a single routine, to
prevent future mistakes with modifying duplicate complex code.
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The check_irq_entry and check_irq_return could be called
from graph event context. In such case there's no graph
private data allocated. Adding checks to handle this case.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <20100924154102.GB1818@jolsa.brq.redhat.com>
[ Fixed some grammar in the comments ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The C version of recordmcount is compiled to a binary, which will
end up located in the objtree. If the kernel is built with O=path,
the srctree will not include the binary recordmcount caller.
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The file kernel/trace/ftrace.c references the mcount() call to
convert the mcount() callers to nops. But because it references
mcount(), the mcount() address is placed in the relocation table.
The C version of recordmcount reads the relocation table of all
object files, and it will add all references to mcount to the
__mcount_loc table that is used to find the places that call mcount()
and change the call to a nop. When recordmcount finds the mcount reference
in kernel/trace/ftrace.o, it saves that location even though the code
is not a call, but references mcount as data.
On boot up, when all calls are converted to nops, the code has a safety
check to determine what op code it is actually replacing before it
replaces it. If that op code at the address does not match, then
a warning is printed and the function tracer is disabled.
The reference to mcount in ftrace.c, causes this warning to trigger,
since the reference is not a call to mcount(). The ftrace.c file is
not compiled with the -pg flag, so no calls to mcount() should be
expected.
This patch simply makes recordmcount.c skip the kernel/trace/ftrace.c
file. This was the same solution used by the perl version of
recordmcount.
Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: John Reiser <jreiser@bitwagon.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Commit e9677b3ce (oprofile, ARM: Use oprofile_arch_exit() to
cleanup on failure) caused oprofile_perf_exit to be called
in the cleanup path of oprofile_perf_init. The __exit tag
for oprofile_perf_exit should therefore be dropped.
The same has to be done for exit_driverfs as well, as this
function is called from oprofile_perf_exit. Else, we get
the following two linker errors.
LD .tmp_vmlinux1
`oprofile_perf_exit' referenced in section `.init.text' of arch/arm/oprofile/built-in.o: defined in discarded section `.exit.text' of arch/arm/oprofile/built-in.o
make: *** [.tmp_vmlinux1] Error 1
LD .tmp_vmlinux1
`exit_driverfs' referenced in section `.text' of arch/arm/oprofile/built-in.o: defined in discarded section `.exit.text' of arch/arm/oprofile/built-in.o
make: *** [.tmp_vmlinux1] Error 1
Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
oprofile_perf.c needs to include platform_device.h
Otherwise we get the following build break.
CC arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.o
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:192: warning: 'struct platform_device' declared inside parameter list
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:192: warning: its scope is only this definition or declaration, which is probably not what you want
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:201: warning: 'struct platform_device' declared inside parameter list
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:210: error: variable 'oprofile_driver' has initializer but incomplete type
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:211: error: unknown field 'driver' specified in initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:211: error: extra brace group at end of initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:211: error: (near initialization for 'oprofile_driver')
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:213: warning: excess elements in struct initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:213: warning: (near initialization for 'oprofile_driver')
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:214: error: unknown field 'resume' specified in initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:214: warning: excess elements in struct initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:214: warning: (near initialization for 'oprofile_driver')
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:215: error: unknown field 'suspend' specified in initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:215: warning: excess elements in struct initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:215: warning: (near initialization for 'oprofile_driver')
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c: In function 'init_driverfs':
Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Peter Zijlstra
Stephane Eranian
Steven Rostedt
Jiri Olsa
matt mooney
Ingo Molnar
Robert Richter
Anand Gadiyar