Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (57 commits)
x86, perf events: Check if we have APIC enabled
perf_event: Fix variable initialization in other codepaths
perf kmem: Fix unused argument build warning
perf symbols: perf_header__read_build_ids() offset'n'size should be u64
perf symbols: dsos__read_build_ids() should read both user and kernel buildids
perf tools: Align long options which have no short forms
perf kmem: Show usage if no option is specified
sched: Mark sched_clock() as notrace
perf sched: Add max delay time snapshot
perf tools: Correct size given to memset
perf_event: Fix perf_swevent_hrtimer() variable initialization
perf sched: Fix for getting task's execution time
tracing/kprobes: Fix field creation's bad error handling
perf_event: Cleanup for cpu_clock_perf_event_update()
perf_event: Allocate children's perf_event_ctxp at the right time
perf_event: Clean up __perf_event_init_context()
hw-breakpoints: Modify breakpoints without unregistering them
perf probe: Update perf-probe document
perf probe: Support --del option
trace-kprobe: Support delete probe syntax
...
In current code, children task will allocate memory for
'child->perf_event_ctxp' if the parent is counted, we can
do it only if the parent allowed children inherit it.
It can save memory and reduce overhead.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4B1F19A8.5040805@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Clean up the code a bit:
- define 'perf_cpu_context' variable with 'static'
- use kzalloc() instead of kmalloc() and memset()
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4B1F194D.7080306@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently, when ptrace needs to modify a breakpoint, like disabling
it, changing its address, type or len, it calls
modify_user_hw_breakpoint(). This latter will perform the heavy and
racy task of unregistering the old breakpoint and registering a new
one.
This is racy as someone else might steal the reserved breakpoint
slot under us, which is undesired as the breakpoint is only
supposed to be modified, sometimes in the middle of a debugging
workflow. We don't want our slot to be stolen in the middle.
So instead of unregistering/registering the breakpoint, just
disable it while we modify its breakpoint fields and re-enable it
after if necessary.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1260347148-5519-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
struct perf_event::event callback was called when a breakpoint
triggers. But this is a rather opaque callback, pretty
tied-only to the breakpoint API and not really integrated into perf
as it triggers even when we don't overflow.
We prefer to use overflow_handler() as it fits into the perf events
rules, being called only when we overflow.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
In the CONFIG_PERF_USE_VMALLOC case, perf_mmap_data_free() only
schedules the cleanup of the perf_mmap_data struct. In that
case we have to wait until the work has been done before we free
data.
Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@kernel.org>
LKML-Reference: <1259697901-1747-1-git-send-email-krh@bitplanet.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When a pinned group cannot be scheduled it goes into error state.
Normally a group cannot go out of error state without being
explicitly re-enabled or disabled. There was a bug in per-thread
mode, whereby upon termination of the thread, the group would
transition from error to off leading to bogus counts and timing
information returned by read().
Fix it by clearing the error state.
Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: perfmon2-devel@lists.sourceforge.net
LKML-Reference: <4b0eb9ce.0508d00a.573b.ffffeab6@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
bp_perf_event_destroy() is unused in its off-case version, let's
remove it to fix the following warning reported by Stephen
Rothwell in linux-next:
kernel/perf_event.c:4306: warning: 'bp_perf_event_destroy' defined but not used
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1259180453-5813-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In fail case, perf_event_create_kernel_counter() returns NULL
instead of an error, which doesn't help us to inform the user
about the origin of the problem from the outer most callers.
Often we can just return -EINVAL, which doesn't help anyone when
it's eventually about a memory allocation failure.
Then, this patch makes perf_event_create_kernel_counter() always
return a detailed error code.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1259210142-5714-2-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit 4ed7c92d68
(perf_events: Undo some recursion damage) has introduced a bad
reference counting of the recursion context. putting the context
behaves like getting it, dropping every software/trace events
after the first one in a context.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1259091502-5171-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When using an event group, the value and id for non leaders events
were wrong due to invalid offset into the outgoing buffer.
Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: paulus@samba.org
Cc: perfmon2-devel@lists.sourceforge.net
LKML-Reference: <4b0b71e1.0508d00a.075e.ffff84a3@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add the remaining necessary bits to support breakpoints created
through perf syscall.
We don't use the software counter interface as:
- We don't need to check against recursion, this is already done
in hardware breakpoints arch level.
- We already know the perf event we are dealing with when the
event is to be committed.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1258987355-8751-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It is quite possible to call update_event_times() on a context
that isn't actually running and thereby confuse the thing.
perf stat was reporting !100% scale values for software counters
(2e2af50b perf_events: Disable events when we detach them,
solved the worst of that, but there was still some left).
The thing that happens is that because we are not self-reaping
(we have a caring parent) there is a time between the last
schedule (out) and having do_exit() called which will detach the
events.
This period would be accounted as enabled,!running because the
event->state==INACTIVE, even though !event->ctx->is_active.
Similar issues could have been observed by calling read() on a
event while the attached task was not scheduled in.
Solve this by teaching update_event_times() about
ctx->is_active.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1258984836.4531.480.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Make perf_swevent_get_recursion_context return a context number
and disable preemption.
This could be used to remove the IRQ disable from the trace bit
and index the per-cpu buffer with.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091123103819.993226816@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move the update_event_times() call in __perf_event_exit_task()
into list_del_event() because that holds the proper lock
(ctx->lock) and seems a more natural place to do the last time
update.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091123103819.842455480@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It appeared we did call update_event_times() on exit, but we
failed to update the context time, which renders the former
moot.
Locking is a bit iffy, we call update_event_times under
ctx->mutex instead of ctx->lock - the next patch fixes this.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091123103819.764207355@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If we leave the event in STATE_INACTIVE, any read of the event
after the detach will increase the running count but not the
enabled count and cause funny scaling artefacts.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091123103819.689055515@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We had two almost identical functions, avoid the duplication.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20091123103819.537537928@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The buffer is first zeroed out by memset(). Then strncpy() is
used to fill the content. The strncpy() function also pads the
string till the end of the specified length, which is redundant.
The strncpy() does not ensures that the string will be properly
closed with 0. Use strlcpy() instead.
The semantic match that finds this kind of pattern is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@@
expression buffer;
expression size;
expression str;
@@
memset(buffer, 0, size);
...
- strncpy(
+ strlcpy(
buffer, str, sizeof(buffer)
);
@@
expression buffer;
expression size;
expression str;
@@
memset(&buffer, 0, size);
...
- strncpy(
+ strlcpy(
&buffer, str, sizeof(buffer));
@@
expression buffer;
identifier field;
expression size;
expression str;
@@
memset(buffer, 0, size);
...
- strncpy(
+ strlcpy(
buffer->field, str, sizeof(buffer->field)
);
@@
expression buffer;
identifier field;
expression size;
expression str;
@@
memset(&buffer, 0, size);
...
- strncpy(
+ strlcpy(
buffer.field, str, sizeof(buffer.field));
// </smpl>
On strncpy() vs strlcpy() see
http://www.gratisoft.us/todd/papers/strlcpy.html .
Signed-off-by: Márton Németh <nm127@freemail.hu>
Cc: Julia Lawall <julia@diku.dk>
Cc: cocci@diku.dk
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4B086547.5040100@freemail.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we commit a trace to perf, we first check if we are
recursing in the same buffer so that we don't mess-up the buffer
with a recursing trace. But later on, we do the same check from
perf to avoid commit recursion. The recursion check is desired
early before we touch the buffer but we want to do this check
only once.
Then export the recursion protection from perf and use it from
the trace events before submitting a trace.
v2: Put appropriate Reported-by tag
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <1258864015-10579-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch fixes the default watermark value for the sampling
buffer. With the existing calculation (watermark =
max(PAGE_SIZE, max_size / 2)), no notification was ever received
when the buffer was exactly 1 page. This was because you would
never cross the threshold (there is no partial samples).
In certain configuration, there was no possibilty detecting the
problem because there was not enough space left to store the
LOST record.In fact, there may be a more generic problem here.
The kernel should ensure that there is alaways enough space to
store one LOST record.
This patch sets the default watermark to half the buffer size.
With such limit, we are guaranteed to get a notification even
with a single page buffer assuming no sample is bigger than a
page.
Signed-off-by: Stephane Eranian <eranian@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212509.344964101@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <1256302576-6169-1-git-send-email-eranian@gmail.com>
We should hold event->child_mutex when iterating the inherited
counters, we should hold ctx->mutex when iterating siblings.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212509.251030114@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Properly account the full hierarchy of counters for both the
count (we already did so) and the scale times (new).
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212509.153379276@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Most sites updating ctx->time and event times do so under
ctx->lock, make sure they all do.
This was made possible by removing the __perf_event_read() call
from __perf_event_sync_stat(), which already had this lock
taken.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212509.102316434@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
cpuctx is always active, task context is always active for
current
the previous condition verifies that if its a task context its
for current, hence we can assume ctx->is_active.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212509.000272254@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Removes constraints from __perf_event_read() by leaving it with
a single callsite; this callsite had ctx->lock held, the other
one does not.
Removes some superfluous code from __perf_event_sync_stat().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.918544317@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Both callers actually have IRQs disabled, no need doing so
again.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.863685796@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove an update_context_time() call from the
perf_event_task_sched_out() path and into the branch its needed.
The call was both superfluous, because __perf_event_sched_out()
already does it, and wrong, because it was done without holding
ctx->lock.
Place it in perf_event_sync_stat(), which is the only place it
is needed and which does already hold ctx->lock.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.779516394@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
As Corey reported, the total_enabled and total_running times
could occasionally be 0, even though there were events counted.
It turns out this is because we record the times before reading
the counter while the latter updates the times.
This patch corrects that.
While looking at this code I found that there is a lot of
locking iffyness around, the following patches correct most of
that.
Reported-by: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.685559857@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove a rcu_read_{,un}lock() pair and a few conditionals.
We can remove the rcu_read_lock() by increasing the scope of one
in the calling function.
We can do away with the system_state check if the machine still
boots after this patch (seems to be the case).
We can do away with the list_empty() check because the bare
list_for_each_entry_rcu() reduces to that now that we've removed
everything else.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.606459548@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove a rcu_read_{,un}lock() pair and a few conditionals.
We can remove the rcu_read_lock() by increasing the scope of one
in the calling function.
We can do away with the system_state check if the machine still
boots after this patch (seems to be the case).
We can do away with the list_empty() check because the bare
list_for_each_entry_rcu() reduces to that now that we've removed
everything else.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.527608793@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove a rcu_read_{,un}lock() pair and a few conditionals.
We can remove the rcu_read_lock() by increasing the scope of one
in the calling function.
We can do away with the system_state check if the machine still
boots after this patch (seems to be the case).
We can do away with the list_empty() check because the bare
list_for_each_entry_rcu() reduces to that now that we've removed
everything else.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.452227115@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove a rcu_read_{,un}lock() pair and a few conditionals.
We can remove the rcu_read_lock() by increasing the scope of one
in the calling function.
We can do away with the system_state check if the machine still
boots after this patch (seems to be the case).
We can do away with the list_empty() check because the bare
list_for_each_entry_rcu() reduces to that now that we've removed
everything else.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.378188589@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Avoid the rather expensive perf_swevent_set_period() if we know
we have to sample every single event anyway.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.299508332@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
in-kernel perf users might wish to have custom actions on the
sample interrupt.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.222339539@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
arch/x86/kernel/kprobes.c
kernel/trace/Makefile
Merge reason: hw-breakpoints perf integration is looking
good in testing and in reviews, plus conflicts
are mounting up - so merge & resolve.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The purpose of perf_output_{un,}lock() is to:
1) avoid publishing incomplete data
[ possible when publishing a head that is ahead of an entry
that is still being written ]
2) guarantee fwd progress
[ a simple refcount on pending writers doesn't need to drop to
0, making it so would end up implementing something like forced
quiecent states of RCU ]
To satisfy the above without undue complexity it serializes
between CPUs, this means that a pending writer can only be the
same cpu in a nested context, and since (under normal operation)
a cpu always makes progress we're good -- if the head is only
published when the bottom most writer completes.
Now we don't need to disable IRQs in order to serialize between
CPUs, disabling preemption ought to be sufficient, esp since we
already deal with nesting due to NMIs.
This avoids potentially expensive (and needless) local IRQ
disable/enable ops.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1258373161.26714.254.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch rebase the implementation of the breakpoints API on top of
perf events instances.
Each breakpoints are now perf events that handle the
register scheduling, thread/cpu attachment, etc..
The new layering is now made as follows:
ptrace kgdb ftrace perf syscall
\ | / /
\ | / /
/
Core breakpoint API /
/
| /
| /
Breakpoints perf events
|
|
Breakpoints PMU ---- Debug Register constraints handling
(Part of core breakpoint API)
|
|
Hardware debug registers
Reasons of this rewrite:
- Use the centralized/optimized pmu registers scheduling,
implying an easier arch integration
- More powerful register handling: perf attributes (pinned/flexible
events, exclusive/non-exclusive, tunable period, etc...)
Impact:
- New perf ABI: the hardware breakpoints counters
- Ptrace breakpoints setting remains tricky and still needs some per
thread breakpoints references.
Todo (in the order):
- Support breakpoints perf counter events for perf tools (ie: implement
perf_bpcounter_event())
- Support from perf tools
Changes in v2:
- Follow the perf "event " rename
- The ptrace regression have been fixed (ptrace breakpoint perf events
weren't released when a task ended)
- Drop the struct hw_breakpoint and store generic fields in
perf_event_attr.
- Separate core and arch specific headers, drop
asm-generic/hw_breakpoint.h and create linux/hw_breakpoint.h
- Use new generic len/type for breakpoint
- Handle off case: when breakpoints api is not supported by an arch
Changes in v3:
- Fix broken CONFIG_KVM, we need to propagate the breakpoint api
changes to kvm when we exit the guest and restore the bp registers
to the host.
Changes in v4:
- Drop the hw_breakpoint_restore() stub as it is only used by KVM
- EXPORT_SYMBOL_GPL hw_breakpoint_restore() as KVM can be built as a
module
- Restore the breakpoints unconditionally on kvm guest exit:
TIF_DEBUG_THREAD doesn't anymore cover every cases of running
breakpoints and vcpu->arch.switch_db_regs might not always be
set when the guest used debug registers.
(Waiting for a reliable optimization)
Changes in v5:
- Split-up the asm-generic/hw-breakpoint.h moving to
linux/hw_breakpoint.h into a separate patch
- Optimize the breakpoints restoring while switching from kvm guest
to host. We only want to restore the state if we have active
breakpoints to the host, otherwise we don't care about messed-up
address registers.
- Add asm/hw_breakpoint.h to Kbuild
- Fix bad breakpoint type in trace_selftest.c
Changes in v6:
- Fix wrong header inclusion in trace.h (triggered a build
error with CONFIG_FTRACE_SELFTEST
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jan Kiszka <jan.kiszka@web.de>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Conflicts:
tools/perf/Makefile
Merge reason: Resolve the conflict, merge to upstream and merge in
perf fixes so we can add a dependent patch.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
