linux-kernel - [PATCH 0/2] perf_counter: fix the group mess

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20090812153529.716542680@chello.nl>
Date:	Wed, 12 Aug 2009 17:35:29 +0200
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Ingo Molnar <mingo@...e.hu>, Paul Mackerras <paulus@...ba.org>,
	stephane eranian <eranian@...glemail.com>
Cc:	Corey J Ashford <cjashfor@...ibm.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/2] perf_counter: fix the group mess


With these two patches the below proglet gives:

# ./test
EVNT: 0xffffffff811c0f4c scale: nan ID: 37 CNT: 1006180 ID: 38 CNT: 1010230 ID: 39 CNT: 1010332 ID: 40 CNT: 1010420

I can't seem to catch the SIGIO thing, but at least all the counters report
more or less the same value.  Also, that scale stuff doesn't seem to quite work
yet.. I'll be poking at that too.



---
#include "perf.h"

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>

void work(void)
{
	int i;

	for (i = 0; i < 1000000000; i++) {
		asm("nop");
		asm("nop");
		asm("nop");
		asm("nop");
		asm("nop");
		asm("nop");
		asm("nop");
	}
}

unsigned long page_size;
int fd = -1, fd1 = 0;
pid_t me;
void *output;

void handle_sigio(int sig)
{
	printf("signal\n"); // not signal safe
	fflush(stdout);

	ioctl(fd, PERF_COUNTER_IOC_REFRESH, 1);
}

static unsigned long mmap_read_head(void)
{
	struct perf_counter_mmap_page *pc = output;
	long head;

	head = pc->data_head;
	rmb();

	return head;
}

static void *mmap_read_base(void)
{
	return output + page_size;
}

struct event {
	struct perf_event_header header;

	u64 ip;
	u64 nr;
	u64 time_enabled;
	u64 time_running;
	struct {
		u64 val;
		u64 id;
	} cnt[0];
};

int main(int argc, char **argv)
{
	struct perf_counter_attr attr;
	unsigned long offset = 0, head;
	int err, i;

	page_size = sysconf(_SC_PAGE_SIZE);
	me = getpid();

	memset(&attr, 0, sizeof(attr));

	attr.type = PERF_TYPE_HARDWARE;
	attr.config = PERF_COUNT_HW_CPU_CYCLES;
	attr.sample_period = 1000000;
	attr.sample_type = PERF_SAMPLE_IP |
			   PERF_SAMPLE_READ;
	attr.read_format = PERF_FORMAT_TOTAL_TIME_RUNNING |
			   PERF_FORMAT_TOTAL_TIME_ENABLED |
			   PERF_FORMAT_ID |
			   PERF_FORMAT_GROUP;
	attr.disabled = 1;
	attr.wakeup_events = 1;

	fd  = sys_perf_counter_open(&attr, me, -1, fd, 0);
	if (fd <= 0) {
		perror("FAIL fd: ");
		exit(-1);
	}

	attr.sample_period = 0;
	attr.disabled = 0;

	for (i = 0; i < 3; i++) {
		fd1 = sys_perf_counter_open(&attr, me, -1, fd, 0);
		if (fd1 <= 0) {
			perror("FAIL fd1: ");
			exit(-1);
		}
	}

	signal(SIGIO, handle_sigio);
	err = fcntl(fd, F_SETOWN, me);
	if (err == -1) {
		perror("FAIL fcntl: ");
		exit(-1);
	}

	output = mmap(NULL, page_size * 3, PROT_READ, MAP_SHARED, fd, 0);
	if (output == ((void *)-1)) {
		perror("FAIL mmap:");
		exit(-1);
	}

	ioctl(fd, PERF_COUNTER_IOC_REFRESH, 1);

	work();

	ioctl(fd, PERF_COUNTER_IOC_DISABLE, 0);

	head = mmap_read_head();

	for (; offset < head; ) {
		struct event *evnt = mmap_read_base() + offset;

		offset += evnt->header.size;

		printf("EVNT: %p scale: %f ", (void *)evnt->ip,
				((double)evnt->time_running)/evnt->time_enabled
				);
		for (i = 0; i < evnt->nr; i++) {
			printf("ID: %Lu CNT: %Lu ", 
					evnt->cnt[i].id, evnt->cnt[i].val);
		}
		printf("\n");
	}

	return 0;
}

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/