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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2010-05-19 10:52:27 +0200
committerIngo Molnar <mingo@elte.hu>2010-05-21 11:37:56 +0200
commitb7e2ecef92d2e7785e6d76b41e5ba8bcbc45259d (patch)
tree341c3a03743108bbdf82ee0eed9f4c4085f1b694 /kernel
parent1c34bde13a3cdcd4c7c6322f8052e67c2c91caf1 (diff)
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perf, trace: Optimize tracepoints by removing IRQ-disable from perf/tracepoint interaction
Improves performance. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1274259525.5605.10352.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_event_perf.c73
-rw-r--r--kernel/trace/trace_kprobe.c10
-rw-r--r--kernel/trace/trace_syscalls.c10
3 files changed, 37 insertions, 56 deletions
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 89b780a7c52..a1304f8c444 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -9,13 +9,9 @@
#include <linux/kprobes.h>
#include "trace.h"
-DEFINE_PER_CPU(struct pt_regs, perf_trace_regs);
-EXPORT_PER_CPU_SYMBOL_GPL(perf_trace_regs);
-
EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs);
-static char *perf_trace_buf;
-static char *perf_trace_buf_nmi;
+static char *perf_trace_buf[4];
/*
* Force it to be aligned to unsigned long to avoid misaligned accesses
@@ -29,7 +25,6 @@ static int total_ref_count;
static int perf_trace_event_enable(struct ftrace_event_call *event, void *data)
{
- char *buf;
int ret = -ENOMEM;
if (event->perf_refcount++ > 0) {
@@ -38,17 +33,16 @@ static int perf_trace_event_enable(struct ftrace_event_call *event, void *data)
}
if (!total_ref_count) {
- buf = (char *)alloc_percpu(perf_trace_t);
- if (!buf)
- goto fail_buf;
-
- rcu_assign_pointer(perf_trace_buf, buf);
+ char *buf;
+ int i;
- buf = (char *)alloc_percpu(perf_trace_t);
- if (!buf)
- goto fail_buf_nmi;
+ for (i = 0; i < 4; i++) {
+ buf = (char *)alloc_percpu(perf_trace_t);
+ if (!buf)
+ goto fail_buf;
- rcu_assign_pointer(perf_trace_buf_nmi, buf);
+ rcu_assign_pointer(perf_trace_buf[i], buf);
+ }
}
ret = event->perf_event_enable(event);
@@ -58,14 +52,15 @@ static int perf_trace_event_enable(struct ftrace_event_call *event, void *data)
return 0;
}
-fail_buf_nmi:
+fail_buf:
if (!total_ref_count) {
- free_percpu(perf_trace_buf_nmi);
- free_percpu(perf_trace_buf);
- perf_trace_buf_nmi = NULL;
- perf_trace_buf = NULL;
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ free_percpu(perf_trace_buf[i]);
+ perf_trace_buf[i] = NULL;
+ }
}
-fail_buf:
event->perf_refcount--;
return ret;
@@ -91,19 +86,19 @@ int perf_trace_enable(int event_id, void *data)
static void perf_trace_event_disable(struct ftrace_event_call *event)
{
- char *buf, *nmi_buf;
-
if (--event->perf_refcount > 0)
return;
event->perf_event_disable(event);
if (!--total_ref_count) {
- buf = perf_trace_buf;
- rcu_assign_pointer(perf_trace_buf, NULL);
+ char *buf[4];
+ int i;
- nmi_buf = perf_trace_buf_nmi;
- rcu_assign_pointer(perf_trace_buf_nmi, NULL);
+ for (i = 0; i < 4; i++) {
+ buf[i] = perf_trace_buf[i];
+ rcu_assign_pointer(perf_trace_buf[i], NULL);
+ }
/*
* Ensure every events in profiling have finished before
@@ -111,8 +106,8 @@ static void perf_trace_event_disable(struct ftrace_event_call *event)
*/
synchronize_sched();
- free_percpu(buf);
- free_percpu(nmi_buf);
+ for (i = 0; i < 4; i++)
+ free_percpu(buf[i]);
}
}
@@ -132,47 +127,37 @@ void perf_trace_disable(int event_id)
}
__kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
- int *rctxp, unsigned long *irq_flags)
+ struct pt_regs *regs, int *rctxp)
{
struct trace_entry *entry;
char *trace_buf, *raw_data;
- int pc, cpu;
+ int pc;
BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
pc = preempt_count();
- /* Protect the per cpu buffer, begin the rcu read side */
- local_irq_save(*irq_flags);
-
*rctxp = perf_swevent_get_recursion_context();
if (*rctxp < 0)
goto err_recursion;
- cpu = smp_processor_id();
-
- if (in_nmi())
- trace_buf = rcu_dereference_sched(perf_trace_buf_nmi);
- else
- trace_buf = rcu_dereference_sched(perf_trace_buf);
-
+ trace_buf = rcu_dereference_sched(perf_trace_buf[*rctxp]);
if (!trace_buf)
goto err;
- raw_data = per_cpu_ptr(trace_buf, cpu);
+ raw_data = per_cpu_ptr(trace_buf, smp_processor_id());
/* zero the dead bytes from align to not leak stack to user */
memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
entry = (struct trace_entry *)raw_data;
- tracing_generic_entry_update(entry, *irq_flags, pc);
+ tracing_generic_entry_update(entry, regs->flags, pc);
entry->type = type;
return raw_data;
err:
perf_swevent_put_recursion_context(*rctxp);
err_recursion:
- local_irq_restore(*irq_flags);
return NULL;
}
EXPORT_SYMBOL_GPL(perf_trace_buf_prepare);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 2d7bf4146be..20c96de0aea 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1343,7 +1343,6 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
struct kprobe_trace_entry_head *entry;
u8 *data;
int size, __size, i;
- unsigned long irq_flags;
int rctx;
__size = sizeof(*entry) + tp->size;
@@ -1353,7 +1352,7 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
"profile buffer not large enough"))
return;
- entry = perf_trace_buf_prepare(size, call->id, &rctx, &irq_flags);
+ entry = perf_trace_buf_prepare(size, call->id, regs, &rctx);
if (!entry)
return;
@@ -1362,7 +1361,7 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
for (i = 0; i < tp->nr_args; i++)
call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
- perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags, regs, call->perf_data);
+ perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, call->perf_data);
}
/* Kretprobe profile handler */
@@ -1374,7 +1373,6 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
struct kretprobe_trace_entry_head *entry;
u8 *data;
int size, __size, i;
- unsigned long irq_flags;
int rctx;
__size = sizeof(*entry) + tp->size;
@@ -1384,7 +1382,7 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
"profile buffer not large enough"))
return;
- entry = perf_trace_buf_prepare(size, call->id, &rctx, &irq_flags);
+ entry = perf_trace_buf_prepare(size, call->id, regs, &rctx);
if (!entry)
return;
@@ -1395,7 +1393,7 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1,
- irq_flags, regs, call->perf_data);
+ regs, call->perf_data);
}
static int probe_perf_enable(struct ftrace_event_call *call)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 9eff1a4b49b..a657cefbb13 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -438,7 +438,6 @@ static void perf_syscall_enter(struct pt_regs *regs, long id)
{
struct syscall_metadata *sys_data;
struct syscall_trace_enter *rec;
- unsigned long flags;
int syscall_nr;
int rctx;
int size;
@@ -461,14 +460,14 @@ static void perf_syscall_enter(struct pt_regs *regs, long id)
return;
rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
- sys_data->enter_event->id, &rctx, &flags);
+ sys_data->enter_event->id, regs, &rctx);
if (!rec)
return;
rec->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args,
(unsigned long *)&rec->args);
- perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs,
+ perf_trace_buf_submit(rec, size, rctx, 0, 1, regs,
sys_data->enter_event->perf_data);
}
@@ -511,7 +510,6 @@ static void perf_syscall_exit(struct pt_regs *regs, long ret)
{
struct syscall_metadata *sys_data;
struct syscall_trace_exit *rec;
- unsigned long flags;
int syscall_nr;
int rctx;
int size;
@@ -537,14 +535,14 @@ static void perf_syscall_exit(struct pt_regs *regs, long ret)
return;
rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
- sys_data->exit_event->id, &rctx, &flags);
+ sys_data->exit_event->id, regs, &rctx);
if (!rec)
return;
rec->nr = syscall_nr;
rec->ret = syscall_get_return_value(current, regs);
- perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs,
+ perf_trace_buf_submit(rec, size, rctx, 0, 1, regs,
sys_data->exit_event->perf_data);
}