leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

perf/core: Add a 'flags' parameter to the PMU transactional interfaces

Browse Source 
Currently, the PMU interface allows reading only one counter at a time.
But some PMUs like the 24x7 counters in Power, support reading several
counters at once. To leveage this functionality, extend the transaction
interface to support a "transaction type".

The first type, PERF_PMU_TXN_ADD, refers to the existing transactions,
i.e. used to _schedule_ all the events on the PMU as a group. A second
transaction type, PERF_PMU_TXN_READ, will be used in a follow-on patch,
by the 24x7 counters to read several counters at once.

Extend the transaction interfaces to the PMU to accept a 'txn_flags'
parameter and use this parameter to ignore any transactions that are
not of type PERF_PMU_TXN_ADD.

Thanks to Peter Zijlstra for his input.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
[peterz: s390 compile fix]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1441336073-22750-3-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Sukadev Bhattiprolu 2015-09-03 20:07:45 -07:00 committed by Ingo Molnar
parent 845583767c
commit fbbe070115
7 changed files with 153 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
arch/powerpc/perf/core-book3s.c
View File

@ -49,6 +49,7 @@ struct cpu_hw_events {
unsigned long avalues[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
unsigned int group_flag;
unsigned int txn_flags;
int n_txn_start;
/* BHRB bits */
@ -1586,11 +1587,21 @@ static void power_pmu_stop(struct perf_event *event, int ef_flags)
* Start group events scheduling transaction
* Set the flag to make pmu::enable() not perform the
* schedulability test, it will be performed at commit time
*
* We only support PERF_PMU_TXN_ADD transactions. Save the
* transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD
* transactions.
*/
static void power_pmu_start_txn(struct pmu *pmu)
static void power_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
{
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */
cpuhw->txn_flags = txn_flags;
if (txn_flags & ~PERF_PMU_TXN_ADD)
return;
perf_pmu_disable(pmu);
cpuhw->group_flag |= PERF_EVENT_TXN;
cpuhw->n_txn_start = cpuhw->n_events;
@ -1604,6 +1615,14 @@ static void power_pmu_start_txn(struct pmu *pmu)
static void power_pmu_cancel_txn(struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
unsigned int txn_flags;
WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
txn_flags = cpuhw->txn_flags;
cpuhw->txn_flags = 0;
if (txn_flags & ~PERF_PMU_TXN_ADD)
return;
cpuhw->group_flag &= ~PERF_EVENT_TXN;
perf_pmu_enable(pmu);
@ -1621,7 +1640,15 @@ static int power_pmu_commit_txn(struct pmu *pmu)
if (!ppmu)
return -EAGAIN;
cpuhw = this_cpu_ptr(&cpu_hw_events);
WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
if (cpuhw->txn_flags & ~PERF_PMU_TXN_ADD) {
cpuhw->txn_flags = 0;
return 0;
}
n = cpuhw->n_events;
if (check_excludes(cpuhw->event, cpuhw->flags, 0, n))
return -EAGAIN;
@ -1633,6 +1660,7 @@ static int power_pmu_commit_txn(struct pmu *pmu)
cpuhw->event[i]->hw.config = cpuhw->events[i];
cpuhw->group_flag &= ~PERF_EVENT_TXN;
cpuhw->txn_flags = 0;
perf_pmu_enable(pmu);
return 0;
}

30
arch/s390/kernel/perf_cpum_cf.c
View File

@ -72,6 +72,7 @@ struct cpu_hw_events {
atomic_t ctr_set[CPUMF_CTR_SET_MAX];
u64 state, tx_state;
unsigned int flags;
unsigned int txn_flags;
};
static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
.ctr_set = {
@ -82,6 +83,7 @@ static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
},
.state = 0,
.flags = 0,
.txn_flags = 0,
};
static int get_counter_set(u64 event)
@ -572,11 +574,21 @@ static void cpumf_pmu_del(struct perf_event *event, int flags)
/*
* Start group events scheduling transaction.
* Set flags to perform a single test at commit time.
*
* We only support PERF_PMU_TXN_ADD transactions. Save the
* transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD
* transactions.
*/
static void cpumf_pmu_start_txn(struct pmu *pmu)
static void cpumf_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
{
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */
cpuhw->txn_flags = txn_flags;
if (txn_flags & ~PERF_PMU_TXN_ADD)
return;
perf_pmu_disable(pmu);
cpuhw->flags |= PERF_EVENT_TXN;
cpuhw->tx_state = cpuhw->state;
@ -589,8 +601,16 @@ static void cpumf_pmu_start_txn(struct pmu *pmu)
*/
static void cpumf_pmu_cancel_txn(struct pmu *pmu)
{
unsigned int txn_flags;
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
txn_flags = cpuhw->txn_flags;
cpuhw->txn_flags = 0;
if (txn_flags & ~PERF_PMU_TXN_ADD)
return;
WARN_ON(cpuhw->tx_state != cpuhw->state);
cpuhw->flags &= ~PERF_EVENT_TXN;
@ -607,6 +627,13 @@ static int cpumf_pmu_commit_txn(struct pmu *pmu)
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
u64 state;
WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
if (cpuhw->txn_flags & ~PERF_PMU_TXN_ADD) {
cpuhw->txn_flags = 0;
return 0;
}
/* check if the updated state can be scheduled */
state = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1);
state >>= CPUMF_LCCTL_ENABLE_SHIFT;
@ -614,6 +641,7 @@ static int cpumf_pmu_commit_txn(struct pmu *pmu)
return -EPERM;
cpuhw->flags &= ~PERF_EVENT_TXN;
cpuhw->txn_flags = 0;
perf_pmu_enable(pmu);
return 0;
}

25
arch/sparc/kernel/perf_event.c
View File

@ -109,6 +109,7 @@ struct cpu_hw_events {
int enabled;
unsigned int group_flag;
unsigned int txn_flags;
};
static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .enabled = 1, };
@ -1494,10 +1495,16 @@ static int sparc_pmu_event_init(struct perf_event *event)
* Set the flag to make pmu::enable() not perform the
* schedulability test, it will be performed at commit time
*/
static void sparc_pmu_start_txn(struct pmu *pmu)
static void sparc_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
{
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */
cpuhw->txn_flags = txn_flags;
if (txn_flags & ~PERF_PMU_TXN_ADD)
return;
perf_pmu_disable(pmu);
cpuhw->group_flag |= PERF_EVENT_TXN;
}
@ -1510,6 +1517,14 @@ static void sparc_pmu_start_txn(struct pmu *pmu)
static void sparc_pmu_cancel_txn(struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
unsigned int txn_flags;
WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
txn_flags = cpuhw->txn_flags;
cpuhw->txn_flags = 0;
if (txn_flags & ~PERF_PMU_TXN_ADD)
return;
cpuhw->group_flag &= ~PERF_EVENT_TXN;
perf_pmu_enable(pmu);
@ -1528,6 +1543,13 @@ static int sparc_pmu_commit_txn(struct pmu *pmu)
if (!sparc_pmu)
return -EINVAL;
WARN_ON_ONCE(!cpuc->txn_flags); /* no txn in flight */
if (cpuc->txn_flags & ~PERF_PMU_TXN_ADD) {
cpuc->txn_flags = 0;
return 0;
}
n = cpuc->n_events;
if (check_excludes(cpuc->event, 0, n))
return -EINVAL;
@ -1535,6 +1557,7 @@ static int sparc_pmu_commit_txn(struct pmu *pmu)
return -EAGAIN;
cpuc->group_flag &= ~PERF_EVENT_TXN;
cpuc->txn_flags = 0;
perf_pmu_enable(pmu);
return 0;
}

32
arch/x86/kernel/cpu/perf_event.c
View File

@ -1748,9 +1748,21 @@ static inline void x86_pmu_read(struct perf_event *event)
* Start group events scheduling transaction
* Set the flag to make pmu::enable() not perform the
* schedulability test, it will be performed at commit time
*
* We only support PERF_PMU_TXN_ADD transactions. Save the
* transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD
* transactions.
*/
static void x86_pmu_start_txn(struct pmu *pmu)
static void x86_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
WARN_ON_ONCE(cpuc->txn_flags); /* txn already in flight */
cpuc->txn_flags = txn_flags;
if (txn_flags & ~PERF_PMU_TXN_ADD)
return;
perf_pmu_disable(pmu);
__this_cpu_or(cpu_hw_events.group_flag, PERF_EVENT_TXN);
__this_cpu_write(cpu_hw_events.n_txn, 0);
@ -1763,6 +1775,16 @@ static void x86_pmu_start_txn(struct pmu *pmu)
*/
static void x86_pmu_cancel_txn(struct pmu *pmu)
{
unsigned int txn_flags;
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
WARN_ON_ONCE(!cpuc->txn_flags); /* no txn in flight */
txn_flags = cpuc->txn_flags;
cpuc->txn_flags = 0;
if (txn_flags & ~PERF_PMU_TXN_ADD)
return;
__this_cpu_and(cpu_hw_events.group_flag, ~PERF_EVENT_TXN);
/*
* Truncate collected array by the number of events added in this
@ -1786,6 +1808,13 @@ static int x86_pmu_commit_txn(struct pmu *pmu)
int assign[X86_PMC_IDX_MAX];
int n, ret;
WARN_ON_ONCE(!cpuc->txn_flags); /* no txn in flight */
if (cpuc->txn_flags & ~PERF_PMU_TXN_ADD) {
cpuc->txn_flags = 0;
return 0;
}
n = cpuc->n_events;
if (!x86_pmu_initialized())
@ -1802,6 +1831,7 @@ static int x86_pmu_commit_txn(struct pmu *pmu)
memcpy(cpuc->assign, assign, n*sizeof(int));
cpuc->group_flag &= ~PERF_EVENT_TXN;
cpuc->txn_flags = 0;
perf_pmu_enable(pmu);
return 0;
}

1
arch/x86/kernel/cpu/perf_event.h
View File

@ -196,6 +196,7 @@ struct cpu_hw_events {
int n_excl; /* the number of exclusive events */
unsigned int group_flag;
unsigned int txn_flags;
int is_fake;
/*

14
include/linux/perf_event.h
View File

@ -201,6 +201,8 @@ struct perf_event;
*/
#define PERF_EVENT_TXN 0x1
#define PERF_PMU_TXN_ADD 0x1 /* txn to add/schedule event on PMU */
/**
* pmu::capabilities flags
*/
@ -331,20 +333,26 @@ struct pmu {
*
* Start the transaction, after this ->add() doesn't need to
* do schedulability tests.
*
* Optional.
*/
void (*start_txn) (struct pmu *pmu); /* optional */
void (*start_txn) (struct pmu *pmu, unsigned int txn_flags);
/*
* If ->start_txn() disabled the ->add() schedulability test
* then ->commit_txn() is required to perform one. On success
* the transaction is closed. On error the transaction is kept
* open until ->cancel_txn() is called.
*
* Optional.
*/
int (*commit_txn) (struct pmu *pmu); /* optional */
int (*commit_txn) (struct pmu *pmu);
/*
* Will cancel the transaction, assumes ->del() is called
* for each successful ->add() during the transaction.
*
* Optional.
*/
void (*cancel_txn) (struct pmu *pmu); /* optional */
void (*cancel_txn) (struct pmu *pmu);
/*
* Will return the value for perf_event_mmap_page::index for this event,

31
kernel/events/core.c
View File

@ -1914,7 +1914,7 @@ group_sched_in(struct perf_event *group_event,
if (group_event->state == PERF_EVENT_STATE_OFF)
return 0;
pmu->start_txn(pmu);
pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
if (event_sched_in(group_event, cpuctx, ctx)) {
pmu->cancel_txn(pmu);
@ -7267,24 +7267,49 @@ static void perf_pmu_nop_void(struct pmu *pmu)
{
}
static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
{
}
static int perf_pmu_nop_int(struct pmu *pmu)
{
return 0;
}
static void perf_pmu_start_txn(struct pmu *pmu)
DEFINE_PER_CPU(unsigned int, nop_txn_flags);
static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
{
__this_cpu_write(nop_txn_flags, flags);
if (flags & ~PERF_PMU_TXN_ADD)
return;
perf_pmu_disable(pmu);
}
static int perf_pmu_commit_txn(struct pmu *pmu)
{
unsigned int flags = __this_cpu_read(nop_txn_flags);
__this_cpu_write(nop_txn_flags, 0);
if (flags & ~PERF_PMU_TXN_ADD)
return 0;
perf_pmu_enable(pmu);
return 0;
}
static void perf_pmu_cancel_txn(struct pmu *pmu)
{
unsigned int flags = __this_cpu_read(nop_txn_flags);
__this_cpu_write(nop_txn_flags, 0);
if (flags & ~PERF_PMU_TXN_ADD)
return;
perf_pmu_enable(pmu);
}
@ -7523,7 +7548,7 @@ got_cpu_context:
pmu->commit_txn = perf_pmu_commit_txn;
pmu->cancel_txn = perf_pmu_cancel_txn;
} else {
pmu->start_txn = perf_pmu_nop_void;
pmu->start_txn = perf_pmu_nop_txn;
pmu->commit_txn = perf_pmu_nop_int;
pmu->cancel_txn = perf_pmu_nop_void;
}