diff options
| author | Paul Mackerras <paulus@samba.org> | 2009-06-17 21:50:04 +1000 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-06-18 11:11:44 +0200 |
| commit | 105988c015943e77092a6568bc5fb7e386df6ccd (patch) | |
| tree | bd352fe5e68a66de2e08a8b91c8f8cccf422f346 /arch/powerpc/kernel/time.c | |
| parent | a73c7d84a1975b44c0ebd03c2dec288af1426349 (diff) | |
perf_counter: powerpc: Enable use of software counters on 32-bit powerpc
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: Paul 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: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/powerpc/kernel/time.c')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 15391c2ab013..eae4511ceeac 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -53,6 +53,7 @@ #include <linux/posix-timers.h> #include <linux/irq.h> #include <linux/delay.h> +#include <linux/perf_counter.h> #include <asm/io.h> #include <asm/processor.h> @@ -525,6 +526,26 @@ void __init iSeries_time_init_early(void) } #endif /* CONFIG_PPC_ISERIES */ +#if defined(CONFIG_PERF_COUNTERS) && defined(CONFIG_PPC32) +DEFINE_PER_CPU(u8, perf_counter_pending); + +void set_perf_counter_pending(void) +{ + get_cpu_var(perf_counter_pending) = 1; + set_dec(1); + put_cpu_var(perf_counter_pending); +} + +#define test_perf_counter_pending() __get_cpu_var(perf_counter_pending) +#define clear_perf_counter_pending() __get_cpu_var(perf_counter_pending) = 0 + +#else /* CONFIG_PERF_COUNTERS && CONFIG_PPC32 */ + +#define test_perf_counter_pending() 0 +#define clear_perf_counter_pending() + +#endif /* CONFIG_PERF_COUNTERS && CONFIG_PPC32 */ + /* * For iSeries shared processors, we have to let the hypervisor * set the hardware decrementer. We set a virtual decrementer @@ -551,6 +572,10 @@ void timer_interrupt(struct pt_regs * regs) set_dec(DECREMENTER_MAX); #ifdef CONFIG_PPC32 + if (test_perf_counter_pending()) { + clear_perf_counter_pending(); + perf_counter_do_pending(); + } if (atomic_read(&ppc_n_lost_interrupts) != 0) do_IRQ(regs); #endif |