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  1. 19 Jun, 2009 6 commits
    • Peter Zijlstra's avatar
      perf_counter: Close race in perf_lock_task_context() · b49a9e7e
      Peter Zijlstra authored 
      perf_lock_task_context() is buggy because it can return a dead
context.

the RCU read lock in perf_lock_task_context() only guarantees
the memory won't get freed, it doesn't guarantee the object is
valid (in our case refcount > 0).

Therefore we can return a locked object that can get freed the
moment we release the rcu read lock.

perf_pin_task_context() then increases the refcount and does an
unlock on freed memory.

That increased refcount will cause a double free, in case it
started out with 0.

Ammend this by including the get_ctx() functionality in
perf_lock_task_context() (all users already did this later
anyway), and return a NULL context when the found one is
already dead.
Signed-off-by: default avatarPeter 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>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b49a9e7e
    • Ingo Molnar's avatar
      perf_counter, x86: Improve interactions with fast-gup · 0c871971
      Ingo Molnar authored 
      Improve a few details in perfcounter call-chain recording that
makes use of fast-GUP:

- Use ACCESS_ONCE() to observe the pte value. ptes are fundamentally
  racy and can be changed on another CPU, so we have to be careful
  about how we access them. The PAE branch is already careful with
  read-barriers - but the non-PAE and 64-bit side needs an
  ACCESS_ONCE() to make sure the pte value is observed only once.

- make the checks a bit stricter so that we can feed it any kind of
  cra^H^H^H user-space input ;-)
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0c871971
    • Peter Zijlstra's avatar
      perf_counter: Simplify and fix task migration counting · e5289d4a
      Peter Zijlstra authored 
      The task migrations counter was causing rare and hard to decypher
memory corruptions under load. After a day of debugging and bisection
we found that the problem was introduced with:

  3f731ca6: perf_counter: Fix cpu migration counter

Turning them off fixes the crashes. Incidentally, the whole
perf_counter_task_migration() logic can be done simpler as well,
by injecting a proper sw-counter event.

This cleanup also fixed the crashes. The precise failure mode is
not completely clear yet, but we are clearly not unhappy about
having a fix ;-)
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      e5289d4a
    • Peter Zijlstra's avatar
      perf_counter tools: Add a data file header · f5970550
      Peter Zijlstra authored 
      Add a data file header so we can transfer data between record and report.

LKML-Reference: <new-submission>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      f5970550
    • Peter Zijlstra's avatar
      perf_counter: Update userspace callchain sampling uses · 2a0a50fe
      Peter Zijlstra authored 
      Update the tools to reflect the new callchain sampling format.

LKML-Reference: <new-submission>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      2a0a50fe
    • Peter Zijlstra's avatar
      perf_counter: Make callchain samples extensible · f9188e02
      Peter Zijlstra authored 
      Before exposing upstream tools to a callchain-samples ABI, tidy it
up to make it more extensible in the future:

Use markers in the IP chain to denote context, use (u64)-1..-4095 range
for these context markers because we use them for ERR_PTR(), so these
addresses are unlikely to be mapped.
Signed-off-by: default avatarPeter 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>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      f9188e02
  3. 18 Jun, 2009 13 commits
    • Ingo Molnar's avatar
      perf report: Filter to parent set by default · b8e6d829
      Ingo Molnar authored 
      Make it easier to use parent filtering - default to a filtered
output. Also add the parent column so that we get collapsing but
dont display it by default.

add --no-exclude-other to override this.

Cc: 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>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b8e6d829
    • Peter Zijlstra's avatar
      perf_counter tools: Handle lost events · 9d91a6f7
      Peter Zijlstra authored 
      Make use of the new ->data_tail mechanism to tell kernel-space
about user-space draining the data stream. Emit lost events
(and display them) if they happen.
Signed-off-by: default avatarPeter 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>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      9d91a6f7
    • Peter Zijlstra's avatar
      perf_counter: Add event overlow handling · 43a21ea8
      Peter Zijlstra authored 
      Alternative method of mmap() data output handling that provides
better overflow management and a more reliable data stream.

Unlike the previous method, that didn't have any user->kernel
feedback and relied on userspace keeping up, this method relies on
userspace writing its last read position into the control page.

It will ensure new output doesn't overwrite not-yet read events,
new events for which there is no space left are lost and the
overflow counter is incremented, providing exact event loss
numbers.
Signed-off-by: default avatarPeter 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>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      43a21ea8
    • Peter Zijlstra's avatar
      fs: Provide empty .set_page_dirty() aop for anon inodes · d3a9262e
      Peter Zijlstra authored 
      .set_page_dirty() is one of those a_ops that defaults to the
buffer implementation when not set. Therefore provide a dummy
function to make it do nothing.

(Uncovered by perfcounters fd's which can now be writable-mmap-ed.)
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davide Libenzi <davidel@xmailserver.org>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d3a9262e
    • Paul Mackerras's avatar
      perf_counter: tools: Makefile tweaks for 64-bit powerpc · e24a72c4
      Paul Mackerras authored 
      On 64-bit powerpc, perf needs to be built as a 64-bit executable.
This arranges to add the -m64 flag to CFLAGS if we are running on
a 64-bit machine, indicated by the result of uname -m ending in "64".
This means that we'll use -m64 on x86_64 machines as well.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55666.866148.559620@cargo.ozlabs.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      e24a72c4
    • Paul Mackerras's avatar
      perf_counter: powerpc: Add processor back-end for MPC7450 family · 7325927e
      Paul Mackerras authored 
      This adds support for the performance monitor hardware on the
MPC7450 family of processors (7450, 7451, 7455, 7447/7457, 7447A,
7448), used in the later Apple G4 powermacs/powerbooks and other
machines.  These machines have 6 hardware counters with a unique
set of events which can be counted on each counter, with some
events being available on multiple counters.

Raw event codes for these processors are (PMC << 8) + PMCSEL.
If PMC is non-zero then the event is that selected by the given
PMCSEL value for that PMC (hardware counter).  If PMC is zero
then the event selected is one of the low-numbered ones that are
common to several PMCs.  In this case PMCSEL must be <= 22 and
the event is what that PMCSEL value would select on PMC1 (but
it may be placed any other PMC that has the same event for that
PMCSEL value).

For events that count cycles or occurrences that exceed a threshold,
the threshold requested can be specified in the 0x3f000 bits of the
raw event codes.  If the event uses the threshold multiplier bit
and that bit should be set, that is indicated with the 0x40000 bit
of the raw event code.

This fills in some of the generic cache events.  Unfortunately there
are quite a few blank spaces in the table, partly because these
processors tend to count cache hits rather than cache accesses.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55631.802122.696927@cargo.ozlabs.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      7325927e
    • Paul Mackerras's avatar
      perf_counter: powerpc: Make powerpc perf_counter code safe for 32-bit kernels · 98fb1807
      Paul Mackerras authored 
      This abstracts a few things in arch/powerpc/kernel/perf_counter.c
that are specific to 64-bit kernels, and provides definitions for
32-bit kernels.  In particular,

* Only 64-bit has MMCRA and the bits in it that give information
  about a PMU interrupt (sampled PR, HV, slot number etc.)
* Only 64-bit has the lppaca and the lppaca->pmcregs_in_use field
* Use of SDAR is confined to 64-bit for now
* Only 64-bit has soft/lazy interrupt disable and therefore
  pseudo-NMIs (interrupts that occur while interrupts are soft-disabled)
* Only 64-bit has PMC7 and PMC8
* Only 64-bit has the MSR_HV bit.

This also fixes the types used in a couple of places, where we were
using long types for things that need to be 64-bit.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55590.634126.876084@cargo.ozlabs.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      98fb1807
    • Paul Mackerras's avatar
      perf_counter: powerpc: Change how processor-specific back-ends get selected · 079b3c56
      Paul Mackerras authored 
      At present, the powerpc generic (processor-independent) perf_counter
code has list of processor back-end modules, and at initialization,
it looks at the PVR (processor version register) and has a switch
statement to select a suitable processor-specific back-end.

This is going to become inconvenient as we add more processor-specific
back-ends, so this inverts the order: now each back-end checks whether
it applies to the current processor, and registers itself if so.
Furthermore, instead of looking at the PVR, back-ends now check the
cur_cpu_spec->oprofile_cpu_type string and match on that.

Lastly, each back-end now specifies a name for itself so the core can
print a nice message when a back-end registers itself.

This doesn't provide any support for unregistering back-ends, but that
wouldn't be hard to do and would allow back-ends to be modules.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55529.762227.518531@cargo.ozlabs.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      079b3c56
    • Paul Mackerras's avatar
      perf_counter: powerpc: Use unsigned long for register and constraint values · 448d64f8
      Paul Mackerras authored 
      This changes the powerpc perf_counter back-end to use unsigned long
types for hardware register values and for the value/mask pairs used
in checking whether a given set of events fit within the hardware
constraints.  This is in preparation for adding support for the PMU
on some 32-bit powerpc processors.  On 32-bit processors the hardware
registers are only 32 bits wide, and the PMU structure is generally
simpler, so 32 bits should be ample for expressing the hardware
constraints.  On 64-bit processors, unsigned long is 64 bits wide,
so using unsigned long vs. u64 (unsigned long long) makes no actual
difference.

This makes some other very minor changes: adjusting whitespace to line
things up in initialized structures, and simplifying some code in
hw_perf_disable().
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55473.26174.331511@cargo.ozlabs.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      448d64f8
    • Paul Mackerras's avatar
      perf_counter: powerpc: Enable use of software counters on 32-bit powerpc · 105988c0
      Paul Mackerras authored 
      This enables the perf_counter subsystem on 32-bit powerpc.  Since we
don't have any support for hardware counters on 32-bit powerpc yet,
only software counters can be used.

Besides selecting HAVE_PERF_COUNTERS for 32-bit powerpc as well as
64-bit, the main thing this does is add an implementation of
set_perf_counter_pending().  This needs to arrange for
perf_counter_do_pending() to be called when interrupts are enabled.
Rather than add code to local_irq_restore as 64-bit does, the 32-bit
set_perf_counter_pending() generates an interrupt by setting the
decrementer to 1 so that a decrementer interrupt will become pending
in 1 or 2 timebase ticks (if a decrementer interrupt isn't already
pending).  When interrupts are enabled, timer_interrupt() will be
called, and some new code in there calls perf_counter_do_pending().
We use a per-cpu array of flags to indicate whether we need to call
perf_counter_do_pending() or not.

This introduces a couple of new Kconfig symbols: PPC_HAVE_PMU_SUPPORT,
which is selected by processor families for which we have hardware PMU
support (currently only PPC64), and PPC_PERF_CTRS, which enables the
powerpc-specific perf_counter back-end.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55404.103840.393470@cargo.ozlabs.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      105988c0
    • Peter Zijlstra's avatar
      perf_counter tools: Add and use isprint() · a73c7d84
      Peter Zijlstra authored 
      Introduce isprint() to print out raw event dumps to ASCII, etc.

(This is an extension to upstream Git's ctype.c.)
Signed-off-by: default avatarPeter 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>
LKML-Reference: <new-submission>
[ removed openssl.h inclusion from util.h - it leaked ctype.h ]
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      a73c7d84
    • Ingo Molnar's avatar
      perf report: Add validation of call-chain entries · 7522060c
      Ingo Molnar authored 
      Add boundary checks for call-chain events. In case of corrupted
entries we could crash otherwise.

Cc: 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>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      7522060c
    • Ingo Molnar's avatar
      perf report: Tidy up the "--parent <regex>" and "--sort parent" call-chain features · b25bcf2f
      Ingo Molnar authored 
      Instead of the ambigious 'call' naming use the much more
specific 'parent' naming:

 - rename --call <regex> to --parent <regex>

 - rename --sort call to --sort parent

 - rename [unmatched] to [other] - to signal that this is not
   an error but the inverse set

Also add pagefaults to the default parent-symbol pattern too,
as it's a 'syscall overhead category' in a sense.

Cc: 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>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b25bcf2f
  5. 17 Jun, 2009 21 commits