Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit bcbcb37c authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter tools: use mmap() output 



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

Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@elte.hu>
parent 803d4f39

Documentation/perf_counter/kerneltop.c

+79 −14
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ 
#include <sys/prctl.h>

#include <sys/wait.h>

#include <sys/uio.h>

#include <sys/mman.h>



#include <linux/unistd.h>
@@ -120,16 +121,24 @@ typedef long long __s64; 


#ifdef __x86_64__

#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 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) {