Bye-bye Performance Counters, welcome Performance Events!
In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.
Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.
All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)
The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.
Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.
User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)
This patch has been generated via the following script:
FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
sed -i \
-e 's/PERF_EVENT_/PERF_RECORD_/g' \
-e 's/PERF_COUNTER/PERF_EVENT/g' \
-e 's/perf_counter/perf_event/g' \
-e 's/nb_counters/nb_events/g' \
-e 's/swcounter/swevent/g' \
-e 's/tpcounter_event/tp_event/g' \
$FILES
for N in $(find . -name perf_counter.[ch]); do
M=$(echo $N | sed 's/perf_counter/perf_event/g')
mv $N $M
done
FILES=$(find . -name perf_event.*)
sed -i \
-e 's/COUNTER_MASK/REG_MASK/g' \
-e 's/COUNTER/EVENT/g' \
-e 's/\<event\>/event_id/g' \
-e 's/counter/event/g' \
-e 's/Counter/Event/g' \
$FILES
... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.
Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.
( NOTE: 'counters' are still the proper terminology when we deal
with hardware registers - and these sed scripts are a bit
over-eager in renaming them. I've undone some of that, but
in case there's something left where 'counter' would be
better than 'event' we can undo that on an individual basis
instead of touching an otherwise nicely automated patch. )
Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
No code changes except printk levels (although some of the K6
mtrr code might be clearer if there were a few as would
splitting out some of the intel cache code).
Signed-off-by: Alan Cox <alan@linux.intel.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
lapic_watchdog_ok() is a global function but no one is using it.
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1246554335.2242.29.camel@jaswinder.satnam>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Expand Intel NMI perfctr1 workaround to include a Core2 processor stepping
(cpuid family-6, model-f, stepping-4). Resolves a situation where the NMI
would not enable on these processors.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: prarit@redhat.com
Cc: suresh.b.siddha@intel.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: rename include file
We'll be providing an asm/perf_counter.h to the generic perfcounter code,
so use the already existing x86 file for this purpose and rename it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There's a small window when NMI watchdog is being set up that if any NMIs
are triggered, the NMI code will make make use of not initalized wd_ops
elements:
void setup_apic_nmi_watchdog(void *unused)
{
if (__get_cpu_var(wd_enabled))
return;
/* cheap hack to support suspend/resume */
/* if cpu0 is not active neither should the other cpus */
if (smp_processor_id() != 0 && atomic_read(&nmi_active) <= 0)
return;
switch (nmi_watchdog) {
case NMI_LOCAL_APIC:
/* enable it before to avoid race with handler */
--> __get_cpu_var(wd_enabled) = 1;
--> if (lapic_watchdog_init(nmi_hz) < 0) {
(...)
asmlinkage notrace __kprobes void default_do_nmi(struct pt_regs *regs)
{
(...)
if (nmi_watchdog_tick(regs, reason))
return;
(...)
notrace __kprobes int
nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
{
(...)
if (!__get_cpu_var(wd_enabled))
return rc;
switch (nmi_watchdog) {
case NMI_LOCAL_APIC:
rc |= lapic_wd_event(nmi_hz);
(...)
int lapic_wd_event(unsigned nmi_hz)
{
struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
u64 ctr;
--> rdmsrl(wd->perfctr_msr, ctr);
and wd->*_msr will be initialized on each processor type specific setup, after
enabling NMIs for PMIs. Since the counter was just set, the chances of an
performance counter generated NMI is minimal, but any other unknown NMI would
trigger the problem. This patch fixes the problem by setting everything up
before enabling performance counter generated NMIs and will set wd_enabled
using a callback function.
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
P4s have a quirk that makes necessary to clear P4_CCCR_OVF bit on the CCCR
everytime the PMI is triggered. When booting the kernel with reset_devices
(more specific kdump case), the counters reach zero and the PMI will be
generated. This is not a problem on other processors but on P4s, it'll
continue to generate NMIs until that bit is cleared. Since there may be
other users of the performance counters, clear and disable all of them
when booting with reset_devices option.
We have a P4 box here that crashes because of this problem. Since the kdump
kernel usually boots with only one processor active, the second logical
unit won't be set up, therefore, MSR_P4_IQ_CCCR1 (and other performance
counter registers) won't be cleared and P4_CCCR_OVF may be still set because
the previous kernel was using this register. An NMI is triggered because of
the MSR_P4_IQ_CCCR1 right after the NMI delivery is enabled, triggering the
race fixed on my previous email.
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently, setup_p4_watchdog() use CCCR_OVF_PMI1 to enable the counter
overflow interrupts to the second logical core. But this bit doesn't work
on Pentium 4 Ds (model 4, stepping 4) and this patch avoids its use on
these processors. Tested on 4 different machines that have this
specific model with success.
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Cc: jvillalovos@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There are a couple of places where (P)Dprintk is used which is an old
compile time enabled printk wrapper. Convert it to the generic
pr_debug().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
It's not even passed on to smp_call_function() anymore, since that
was removed. So kill it.
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This patch does check if CPU is being recongnized
before call the unreserve(). Since enable_lapic_nmi_watchdog()
does have such a check the same is make sense here too
in a sake of code consistency (but nothing more).
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: macro@linux-mips.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
There apparently was an unnoticed conflict between an earlier patch to
this file and mine (d1e084746b), which
I noticed only now. I suppose a change like the one below (untested) is
needed; I didn't get any response on a confirmation request for this from
the submitter of the first patch.
The issue is the writing of the 'checkbit' member at the end of
setup_intel_arch_watchdog(), which my patch made go to intel_arch_wd_ops
rather than wd_ops.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
right now if there's no CPU support for nmi_watchdog=2 we'll just
refuse it silently.
print a useful warning.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
implement nmi_watchdog=2 on this class of CPUs:
cpu family : 15
model : 6
model name : Intel(R) Pentium(R) D CPU 3.00GHz
the watchdog's ->setup() method is safe anyway, so if the CPU
cannot support it we'll bail out safely.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Here is a small patch to change the behavior of the PMU msr allocator
to avoid BUG_ON() when the MSR is unknwon. Instead, it now returns
ok, which means "I do not manage". The current allocator is not
yet managing the full set of PMU registers (e.g., GLOBAL_* on Core 2).
[watchdog] do not BUG_ON() in the MSR allocator if MSR is unknown, return ok
instead
Signed-off-by: Stephane Eranian <eranian@hpl.hp.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
.. as they're, with a single exception, never written to.
[ tglx: arch/x86 adaptation ]
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Ingo Molnar