/*

 * ita2_btb.c - example of how use the BTB with the Itanium 2 PMU

 *

 * Copyright (c) 2003-2006 Hewlett-Packard Development Company, L.P.

 * Contributed by Stephane Eranian <eranian@hpl.hp.com>

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies

 * of the Software, and to permit persons to whom the Software is furnished to do so,

 * subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in all

 * copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,

 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A

 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF

 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE

 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 *

 * This file is part of libpfm, a performance monitoring support library for

 * applications on Linux.

 */

#include <sys/types.h>

#include <stdio.h>

#include <stdlib.h>

#include <stdarg.h>

#include <errno.h>

#include <unistd.h>

#include <string.h>

#include <signal.h>

#include <fcntl.h>

#include <sys/mman.h>

#include <perfmon/perfmon.h>

#include <perfmon/perfmon_dfl_smpl.h>

#include <perfmon/pfmlib_itanium2.h>

typedef pfm_dfl_smpl_hdr_t	btb_hdr_t;

typedef pfm_dfl_smpl_entry_t	btb_entry_t;

typedef pfm_dfl_smpl_arg_t	smpl_arg_t;

#define NUM_PMCS PFMLIB_MAX_PMCS

#define NUM_PMDS PFMLIB_MAX_PMDS

#define MAX_EVT_NAME_LEN	128

#define MAX_PMU_NAME_LEN	32

/*

 * The BRANCH_EVENT is increment by 1 for each branch event. Such event is composed of

 * two entries in the BTB: a source and a target entry. The BTB is full after 4 branch

 * events.

 */

#define SMPL_PERIOD	(4UL*256)

static void *smpl_vaddr;

static unsigned int entry_size;

static int id;

#define BPL (sizeof(uint64_t)<<3)

#define LBPL	6

static inline void pfm_bv_set(uint64_t *bv, uint16_t rnum)

{

	bv[rnum>>LBPL] |= 1UL << (rnum&(BPL-1));

}

/*

 * we don't use static to make sure the compiler does not inline the function

 */

long func1(void) { return 0;}

long

do_test(unsigned long loop)

{

	long sum  = 0;

	while(loop--) {

		if (loop & 0x1)

			sum += func1();

		else

			sum += loop;

	}

	return sum;

}

static void fatal_error(char *fmt,...) __attribute__((noreturn));

static void

fatal_error(char *fmt, ...)

{

	va_list ap;

	va_start(ap, fmt);

	vfprintf(stderr, fmt, ap);

	va_end(ap);

	exit(1);

}

/*

 * print content of sampling buffer

 *

 * XXX: using stdio to print from a signal handler is not safe with multi-threaded

 * applications

 */

#define safe_printf	printf

static void

show_btb_reg(int j, pfm_ita2_pmd_reg_t reg, pfm_ita2_pmd_reg_t pmd16)

{

	unsigned long bruflush, b1;

	int is_valid = reg.pmd8_15_ita2_reg.btb_b == 0 && reg.pmd8_15_ita2_reg.btb_mp == 0 ? 0 :1;

	b1       = (pmd16.pmd_val >> (4 + 4*(j-8))) & 0x1;

	bruflush = (pmd16.pmd_val >> (5 + 4*(j-8))) & 0x1;

	safe_printf("\tPMD%-2d: 0x%016lx b=%d mp=%d bru=%ld b1=%ld valid=%c\n",

		j,

		reg.pmd_val,

		 reg.pmd8_15_ita2_reg.btb_b,

		 reg.pmd8_15_ita2_reg.btb_mp,

		 bruflush, b1,

		is_valid ? 'Y' : 'N');

	if (!is_valid) return;

	if (reg.pmd8_15_ita2_reg.btb_b) {

		unsigned long addr;

		addr = (reg.pmd8_15_ita2_reg.btb_addr+b1)<<4;

		addr |= reg.pmd8_15_ita2_reg.btb_slot < 3 ?  reg.pmd8_15_ita2_reg.btb_slot : 0;

		safe_printf("\t       Source Address: 0x%016lx\n"

			    "\t       Taken=%c Prediction: %s\n\n",

			 addr,

			 reg.pmd8_15_ita2_reg.btb_slot < 3 ? 'Y' : 'N',

			 reg.pmd8_15_ita2_reg.btb_mp ? "FE Failure" :

			 bruflush ? "BE Failure" : "Success");

	} else {

		safe_printf("\t       Target Address: 0x%016lx\n\n",

			 (unsigned long)(reg.pmd8_15_ita2_reg.btb_addr<<4));

	}

}

static void

show_btb(pfm_ita2_pmd_reg_t *btb, pfm_ita2_pmd_reg_t *pmd16)

{

	int i, last;

	i    = (pmd16->pmd16_ita2_reg.btbi_full) ? pmd16->pmd16_ita2_reg.btbi_bbi : 0;

	last = pmd16->pmd16_ita2_reg.btbi_bbi;

	safe_printf("btb_trace: i=%d last=%d bbi=%d full=%d\n", i, last,pmd16->pmd16_ita2_reg.btbi_bbi, pmd16->pmd16_ita2_reg.btbi_full);

	do {

		show_btb_reg(i+8, btb[i], *pmd16);

		i = (i+1) % 8;

	} while (i != last);

}

void

process_smpl_buffer(void)

{

	btb_hdr_t	*hdr;

	btb_entry_t	*ent;

	unsigned long pos;

	unsigned long smpl_entry = 0;

	pfm_ita2_pmd_reg_t *reg, *pmd16;

	unsigned long i;

	int ret;

	static unsigned long last_ovfl = ~0UL;

	hdr = (btb_hdr_t *)smpl_vaddr;

	/*

	 * check that we are not diplaying the previous set of samples again.

	 * Required to take care of the last batch of samples.

	 */

	if (hdr->hdr_overflows <= last_ovfl && last_ovfl != ~0UL) {

		printf("skipping identical set of samples %lu <= %lu\n", hdr->hdr_overflows, last_ovfl);

		return;

	}

	pos = (unsigned long)(hdr+1);

	/*

	 * walk through all the entries recored in the buffer

	 */

	for(i=0; i < hdr->hdr_count; i++) {

		ret = 0;

		ent = (btb_entry_t *)pos;

		/*

		 * print entry header

		 */

		safe_printf("Entry %ld PID:%d TID:%d CPU:%d STAMP:0x%lx IIP:0x%016lx\n",

			smpl_entry++,

			ent->tgid,

			ent->pid,

			ent->cpu,

			ent->tstamp,

			ent->ip);

		/*

		 * point to first recorded register (always contiguous with entry header)

		 */

		reg = (pfm_ita2_pmd_reg_t*)(ent+1);

		/*

		 * in this particular example, we have pmd8-pmd15 has the BTB. We have also

		 * included pmd16 (BTB index) has part of the registers to record. This trick

		 * allows us to get the index to decode the sequential order of the BTB.

		 *

		 * Recorded registers are always recorded in increasing order. So we know

		 * that pmd16 is at a fixed offset (+8*sizeof(unsigned long)) from pmd8.

		 */

		pmd16 = reg+8;

		show_btb(reg, pmd16);

		/*

		 * move to next entry

		 */

		pos += entry_size;

	}

}

static void

overflow_handler(int n, struct siginfo *info, struct sigcontext *sc)

{

	/* dangerous */

	printf("Notification received\n");

	process_smpl_buffer();

	/*

	 * And resume monitoring

	 */

	if (pfm_restart(id) == -1) {

		perror("pfm_restart");

		exit(1);

	}

}

int

main(void)

{

	int ret;

	int type = 0;

	pfarg_pmd_t pd[NUM_PMDS];

	pfarg_pmc_t pc[NUM_PMCS];

	pfmlib_input_param_t inp;

	pfmlib_output_param_t outp;

	pfmlib_ita2_input_param_t ita2_inp;

	pfarg_ctx_t ctx;

	smpl_arg_t buf_arg;

	pfarg_load_t load_args;

	pfmlib_options_t pfmlib_options;

	struct sigaction act;

	unsigned int i;

	/*

	 * Initialize pfm library (required before we can use it)

	 */

	ret = pfm_initialize();

	if (ret != PFMLIB_SUCCESS)

		fatal_error("Cannot initialize library: %s\n", pfm_strerror(ret));

	/*

	 * Let's make sure we run this on the right CPU

	 */

	pfm_get_pmu_type(&type);

	if (type != PFMLIB_ITANIUM2_PMU) {

		char model[MAX_PMU_NAME_LEN];

		pfm_get_pmu_name(model, MAX_PMU_NAME_LEN);

		fatal_error("this program does not work with %s PMU\n", model);

	}

	/*

	 * Install the overflow handler (SIGIO)

	 */

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

	act.sa_handler = (sig_t)overflow_handler;

	sigaction (SIGIO, &act, 0);

	/*

	 * pass options to library (optional)

	 */

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

	pfmlib_options.pfm_debug = 0; /* set to 1 for debug */

	pfmlib_options.pfm_verbose = 1; /* set to 1 for debug */

	pfm_set_options(&pfmlib_options);

	memset(pd, 0, sizeof(pd));

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

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

	/*

	 * prepare parameters to library. we don't use any Itanium

	 * specific features here. so the pfp_model is NULL.

	 */

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

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

	memset(&ita2_inp,0, sizeof(ita2_inp));

	/*

	 * Before calling pfm_find_dispatch(), we must specify what kind

	 * of branches we want to capture. We are interested in all the

	 * mispredicted (target, taken/not taken) branches, therefore we

	 * program the various fields of the BTB config to:

	 */

	ita2_inp.pfp_ita2_btb.btb_used = 1;

	ita2_inp.pfp_ita2_btb.btb_ds  = 0;   /* capture target */

	ita2_inp.pfp_ita2_btb.btb_tm  = 0x3; /* all branches */

	ita2_inp.pfp_ita2_btb.btb_ptm = 0x1; /* target mispredicted */

	ita2_inp.pfp_ita2_btb.btb_ppm = 0x1; /* mispredicted path */

	ita2_inp.pfp_ita2_btb.btb_brt = 0x0; /* all types captured */

	ita2_inp.pfp_ita2_btb.btb_plm = PFM_PLM3;

	if (pfm_find_full_event("BRANCH_EVENT", &inp.pfp_events[0]) != PFMLIB_SUCCESS) {

		fatal_error("cannot find event BRANCH_EVENT\n");

	}

	/*

	 * set the (global) privilege mode:

	 * 	PFM_PLM3 : user level only

	 */

	inp.pfp_dfl_plm   = PFM_PLM3;

	/*

	 * how many counters we use

	 */

	inp.pfp_event_count = 1;

	/*

	 * let the library figure out the values for the PMCS

	 */

	if ((ret=pfm_dispatch_events(&inp, &ita2_inp, &outp, NULL)) != PFMLIB_SUCCESS) {

		fatal_error("cannot configure events: %s\n", pfm_strerror(ret));

	}

	/*

	 * the size of the buffer is indicated in bytes (not entries).

	 *

	 * The kernel will record into the buffer up to a certain point.

	 * No partial samples are ever recorded.

	 */

	buf_arg.buf_size = getpagesize();

	/*

	 * now create the context for self monitoring/per-task

	 */

	id = pfm_create_context(&ctx, "default", &buf_arg, sizeof(buf_arg));

	if (id == -1) {

		if (errno == ENOSYS) {

			fatal_error("Your kernel does not have performance monitoring support!\n");

		}

		fatal_error("Can't create PFM context %s\n", strerror(errno));

	}

	/*

	 * retrieve the virtual address at which the sampling

	 * buffer has been mapped

	 */

	smpl_vaddr = mmap(NULL, (size_t)buf_arg.buf_size, PROT_READ, MAP_PRIVATE, id, 0);

	if (smpl_vaddr == MAP_FAILED)

		fatal_error("cannot mmap sampling buffer errno %d\n", errno);

	printf("Sampling buffer mapped at %p\n", smpl_vaddr);

	/*

	 * Now prepare the argument to initialize the PMDs and PMCS.

	 * We must pfp_pmc_count to determine the number of PMC to intialize.

	 * We must use pfp_event_count to determine the number of PMD to initialize.

	 * Some events cause extra PMCs to be used, so  pfp_pmc_count may be >= pfp_event_count.

	 *

	 * This step is new compared to libpfm-2.x. It is necessary because the library no

	 * longer knows about the kernel data structures.

	 */

	for (i=0; i < outp.pfp_pmc_count; i++) {

		pc[i].reg_num   = outp.pfp_pmcs[i].reg_num;

		pc[i].reg_value = outp.pfp_pmcs[i].reg_value;

	}

	/*

	 * figure out pmd mapping from output pmc

	 * PMD16 is part of the set of used PMD returned by libpfm.

	 * It will be reset automatically

	 */

	for (i=0; i < outp.pfp_pmd_count; i++)

		pd[i].reg_num   = outp.pfp_pmds[i].reg_num;

	/*

	 * indicate we want notification when buffer is full

	 */

	pd[0].reg_flags |= PFM_REGFL_OVFL_NOTIFY;

	/*

	 * Now prepare the argument to initialize the PMD and the sampling period

	 * We know we use only one PMD in this case, therefore pmd[0] corresponds

	 * to our first event which is our sampling period.

	 */

	pd[0].reg_value       = - SMPL_PERIOD;

	pd[0].reg_long_reset  = - SMPL_PERIOD;

	pd[0].reg_short_reset = - SMPL_PERIOD;

	pfm_bv_set(pd[0].reg_smpl_pmds, 16);

	entry_size = sizeof(btb_entry_t) + 1 * 8;

	for(i=8; i < 16; i++) {

		pfm_bv_set(pd[0].reg_smpl_pmds, i);

		entry_size += 8;

	}

	/*

	 * When our counter overflows, we want to BTB index to be reset, so that we keep

	 * in sync. This is required to make it possible to interpret pmd16 on overflow

	 * to avoid repeating the same branch several times.

	 */

	pfm_bv_set(pd[0].reg_reset_pmds, 16);

		/*

	 * Now program the registers

	 */

	if (pfm_write_pmcs(id, pc, outp.pfp_pmc_count) == -1)

		fatal_error("pfm_write_pmcs error errno %d\n",errno);

	if (pfm_write_pmds(id, pd, outp.pfp_pmd_count) == -1)

		fatal_error("pfm_write_pmds error errno %d\n",errno);

	/*

	 * now we load (i.e., attach) the context to ourself

	 */

	load_args.load_pid = getpid();

	if (pfm_load_context(id, &load_args) == -1)

		fatal_error("pfm_load_context error errno %d\n",errno);

	/*

	 * setup asynchronous notification on the file descriptor

	 */

	ret = fcntl(id, F_SETFL, fcntl(id, F_GETFL, 0) | O_ASYNC);

	if (ret == -1)

		fatal_error("cannot set ASYNC: %s\n", strerror(errno));

	/*

	 * get ownership of the descriptor

	 */

	ret = fcntl(id, F_SETOWN, getpid());

	if (ret == -1)

		fatal_error("cannot setown: %s\n", strerror(errno));

	/*

	 * Let's roll now.

	 */

	pfm_self_start(id);

	do_test(100000);

	pfm_self_stop(id);

	/*

	 * We must call the processing routine to cover the last entries recorded

	 * in the sampling buffer. Note that the buffer may not be full at this point.

	 *

	 */

	process_smpl_buffer();

	/*

	 * let's stop this now

	 */

	munmap(smpl_vaddr, (size_t)buf_arg.buf_size);

	close(id);

	return 0;

}