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perf_counter tools: use mmap() output

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update kerneltop to use the mmap() output to gather overflow information

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090323172417.677932499@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-03-23 18:22:12 +01:00 committed by Ingo Molnar
parent 803d4f3980
commit bcbcb37cdb
1 changed files with 79 additions and 14 deletions
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93
Documentation/perf_counter/kerneltop.c
View file

@ -84,6 +84,7 @@
#include <sys/prctl.h>
#include <sys/wait.h>
#include <sys/uio.h>
#include <sys/mman.h>
#include <linux/unistd.h>
@ -119,17 +120,25 @@ typedef long long __s64;
#ifdef __x86_64__
# define __NR_perf_counter_open 295
#define __NR_perf_counter_open 295
#define rmb() asm volatile("lfence" ::: "memory")
#define cpu_relax() asm volatile("rep; nop" ::: "memory");
#endif
#ifdef __i386__
# define __NR_perf_counter_open 333
#define __NR_perf_counter_open 333
#define rmb() asm volatile("lfence" ::: "memory")
#define cpu_relax() asm volatile("rep; nop" ::: "memory");
#endif
#ifdef __powerpc__
#define __NR_perf_counter_open 319
#define rmb() asm volatile ("sync" ::: "memory")
#define cpu_relax() asm volatile ("" ::: "memory");
#endif
#define unlikely(x) __builtin_expect(!!(x), 0)
asmlinkage int sys_perf_counter_open(
struct perf_counter_hw_event *hw_event_uptr __user,
pid_t pid,
@ -181,6 +190,7 @@ static int profile_cpu = -1;
static int nr_cpus = 0;
static int nmi = 1;
static int group = 0;
static unsigned int page_size;
static char *vmlinux;
@ -1117,16 +1127,68 @@ static void process_options(int argc, char *argv[])
}
}
struct mmap_data {
int counter;
void *base;
unsigned int mask;
unsigned int prev;
};
static unsigned int mmap_read_head(struct mmap_data *md)
{
struct perf_counter_mmap_page *pc = md->base;
unsigned int seq, head;
repeat:
rmb();
seq = pc->lock;
if (unlikely(seq & 1)) {
cpu_relax();
goto repeat;
}
head = pc->data_head;
rmb();
if (pc->lock != seq)
goto repeat;
return head;
}
static void mmap_read(struct mmap_data *md)
{
unsigned int head = mmap_read_head(md);
unsigned int old = md->prev;
unsigned char *data = md->base + page_size;
if (head - old > md->mask) {
printf("ERROR: failed to keep up with mmap data\n");
exit(-1);
}
for (; old != head;) {
__u64 *ptr = (__u64 *)&data[old & md->mask];
old += sizeof(__u64);
process_event(*ptr, md->counter);
}
md->prev = old;
}
int main(int argc, char *argv[])
{
struct pollfd event_array[MAX_NR_CPUS][MAX_COUNTERS];
struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
struct perf_counter_hw_event hw_event;
int i, counter, group_fd;
unsigned int cpu;
uint64_t ip;
ssize_t res;
int ret;
page_size = sysconf(_SC_PAGE_SIZE);
process_options(argc, argv);
nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
@ -1153,8 +1215,6 @@ int main(int argc, char *argv[])
hw_event.record_type = PERF_RECORD_IRQ;
hw_event.nmi = nmi;
printf("FOO: %d %llx %llx\n", counter, event_id[counter], event_count[counter]);
fd[i][counter] = sys_perf_counter_open(&hw_event, tid, cpu, group_fd, 0);
fcntl(fd[i][counter], F_SETFL, O_NONBLOCK);
if (fd[i][counter] < 0) {
@ -1174,6 +1234,17 @@ int main(int argc, char *argv[])
event_array[i][counter].fd = fd[i][counter];
event_array[i][counter].events = POLLIN;
mmap_array[i][counter].counter = counter;
mmap_array[i][counter].prev = 0;
mmap_array[i][counter].mask = 2*page_size - 1;
mmap_array[i][counter].base = mmap(NULL, 3*page_size,
PROT_READ, MAP_SHARED, fd[i][counter], 0);
if (mmap_array[i][counter].base == MAP_FAILED) {
printf("kerneltop error: failed to mmap with %d (%s)\n",
errno, strerror(errno));
exit(-1);
}
}
}
@ -1188,14 +1259,8 @@ int main(int argc, char *argv[])
int hits = events;
for (i = 0; i < nr_cpus; i++) {
for (counter = 0; counter < nr_counters; counter++) {
res = read(fd[i][counter], (char *) &ip, sizeof(ip));
if (res > 0) {
assert(res == sizeof(ip));
process_event(ip, counter);
}
}
for (counter = 0; counter < nr_counters; counter++)
mmap_read(&mmap_array[i][counter]);
}
if (time(NULL) >= last_refresh + delay_secs) {