linux-stable.git/tools/perf/util/thread-stack.c, branch linux-5.0.y

perf thread-stack: Fix thread stack processing for the idle task

2019-01-02T14:03:17+00:00

perf creates a single 'struct thread' to represent the idle task. That
is because threads are identified by PID and TID, and the idle task
always has PID == TID == 0.

However, there are actually separate idle tasks for each CPU. That
creates a problem for thread stack processing which assumes that each
thread has a single stack, not one stack per CPU.

Fix that by passing through the CPU number, and in the case of the idle
"thread", pick the thread stack from an array based on the CPU number.

Signed-off-by: Adrian Hunter 
Acked-by: Jiri Olsa 
Link: http://lkml.kernel.org/r/20181221120620.9659-8-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Allocate an array of thread stacks

2019-01-02T13:55:55+00:00

In preparation for fixing thread stack processing for the idle task,
allocate an array of thread stacks.

Signed-off-by: Adrian Hunter 
Acked-by: Jiri Olsa 
Link: http://lkml.kernel.org/r/20181221120620.9659-7-adrian.hunter@intel.com
[ No need to check for NULL when calling zfree(), noticed by Jiri Olsa ]
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Factor out thread_stack__init()

2019-01-02T13:53:41+00:00

In preparation for fixing thread stack processing for the idle task,
factor out thread_stack__init().

Signed-off-by: Adrian Hunter 
Acked-by: Jiri Olsa 
Link: http://lkml.kernel.org/r/20181221120620.9659-6-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Allow for a thread stack array

2019-01-02T13:49:51+00:00

In preparation for fixing thread stack processing for the idle task,
allow for a thread stack array.

Signed-off-by: Adrian Hunter 
Acked-by: Jiri Olsa 
Link: http://lkml.kernel.org/r/20181221120620.9659-5-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Avoid direct reference to the thread's stack

2019-01-02T13:48:18+00:00

In preparation for fixing thread stack processing for the idle task,
avoid direct reference to the thread's stack. The thread stack will
change to an array of thread stacks, at which point the meaning of the
direct reference will change.

Signed-off-by: Adrian Hunter 
Acked-by: Jiri Olsa 
Link: http://lkml.kernel.org/r/20181221120620.9659-4-adrian.hunter@intel.com
[ Rename thread_stack__ts() to thread__stack() since this operates on a 'thread' struct ]
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Tidy thread_stack__bottom() usage

2019-01-02T13:45:26+00:00

In preparation for fixing thread stack processing for the idle task,
tidy thread_stack__bottom() usage. Specifically, the parameter 'thread'
is not needed.

Signed-off-by: Adrian Hunter 
Acked-by: Jiri Olsa 
Link: http://lkml.kernel.org/r/20181221120620.9659-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Simplify some code in thread_stack__process()

2019-01-02T13:42:45+00:00

In preparation for fixing thread stack processing for the idle task,
simplify some code in thread_stack__process().

Signed-off-by: Adrian Hunter 
Acked-by: Jiri Olsa 
Link: http://lkml.kernel.org/r/20181221120620.9659-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Insert callchain context into synthesized callchains

2018-10-31T15:54:27+00:00

In the absence of a fallback, callchains must encode also the callchain
context. Do that now there is no fallback.

Signed-off-by: Adrian Hunter 
Reviewed-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: David S. Miller 
Cc: Leo Yan 
Cc: Mathieu Poirier 
Cc: stable@vger.kernel.org # 4.19
Link: http://lkml.kernel.org/r/100ea2ec-ed14-b56d-d810-e0a6d2f4b069@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Improve thread_stack__process() for trace begin / end

2018-09-20T18:19:50+00:00

thread_stack__process() is used to create call paths for database
export.  Improve the handling of trace begin / end to allow for a trace
that ends in a call.

Previously, the Intel PT decoder would indicate begin / end by a branch
from / to zero. That hides useful information, in particular when a
trace ends with a call. Before remedying that, enhance the thread stack
so that it identifies the trace end by the flag instead of by ip == 0.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lkml.kernel.org/r/20180920130048.31432-5-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Improve thread_stack__event() for trace begin / end

2018-09-20T18:16:17+00:00

thread_stack__event() is used to create call stacks, by keeping track of
calls and returns. Improve the handling of trace begin / end to allow
for a trace that ends in a call.

Previously, the Intel PT decoder would indicate begin / end by a branch
from / to zero. That hides useful information, in particular when a
trace ends with a call. Before remedying that, enhance the thread stack
so that it does not expect to see the 'return' for a 'call' that ends
the trace.

Committer notes:

Added this:

                return thread_stack__push(thread->ts, ret_addr,
-                                         flags && PERF_IP_FLAG_TRACE_END);
+                                         flags & PERF_IP_FLAG_TRACE_END);

To fix problem spotted by:

debian:9:            clang version 3.8.1-24 (tags/RELEASE_381/final)
debian:experimental: clang version 6.0.1-6 (tags/RELEASE_601/final)

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lkml.kernel.org/r/20180920130048.31432-4-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo