/*

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

 *

 * Copyright (c) 2002-2006 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/ia64.

 */

#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 <perfmon/perfmon.h>

#include <perfmon/perfmon_default_smpl.h>

#include <perfmon/pfmlib_itanium.h>

typedef pfm_default_smpl_hdr_t	btb_hdr_t;

typedef pfm_default_smpl_entry_t	btb_entry_t;

typedef pfm_default_smpl_ctx_arg_t	btb_ctx_arg_t;

#define BTB_FMT_UUID	        	PFM_DEFAULT_SMPL_UUID

static pfm_uuid_t buf_fmt_id = BTB_FMT_UUID;

#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)

/*

 * We use a small buffer size to exercise the overflow handler

 */

#define SMPL_BUF_NENTRIES	64

#define M_PMD(x)		(1UL<<(x))

#define BTB_REGS_MASK		(M_PMD(8)|M_PMD(9)|M_PMD(10)|M_PMD(11)|M_PMD(12)|M_PMD(13)|M_PMD(14)|M_PMD(15)|M_PMD(16))

static void *smpl_vaddr;

static unsigned int entry_size;

static int id;

#if defined(__ECC) && defined(__INTEL_COMPILER)

/* if you do not have this file, your compiler is too old */

#include <ia64intrin.h>

#define hweight64(x)	_m64_popcnt(x)

#elif defined(__GNUC__)

static __inline__ int

hweight64 (unsigned long x)

{

	unsigned long result;

	__asm__ ("popcnt %0=%1" : "=r" (result) : "r" (x));

	return (int)result;

}

#else

#error "you need to provide inline assembly from your compiler"

#endif

/*

 * 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 int

show_btb_reg(int j, pfm_ita_pmd_reg_t reg)

{

	int ret;

	int is_valid = reg.pmd8_15_ita_reg.btb_b == 0 && reg.pmd8_15_ita_reg.btb_mp == 0 ? 0 :1;

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

			j,

			reg.pmd_val,

			 reg.pmd8_15_ita_reg.btb_b,

			 reg.pmd8_15_ita_reg.btb_mp,

			is_valid ? 'Y' : 'N');

	if (!is_valid) return ret;

	if (reg.pmd8_15_ita_reg.btb_b) {

		unsigned long addr;

		addr = 	reg.pmd8_15_ita_reg.btb_addr<<4;

		addr |= reg.pmd8_15_ita_reg.btb_slot < 3 ?  reg.pmd8_15_ita_reg.btb_slot : 0;

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

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

			 addr,

			 reg.pmd8_15_ita_reg.btb_slot < 3 ? 'Y' : 'N',

			 reg.pmd8_15_ita_reg.btb_mp ? "Failure" : "Success");

	} else {

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

			 (unsigned long)reg.pmd8_15_ita_reg.btb_addr<<4);

	}

	return ret;

}

static void

show_btb(pfm_ita_pmd_reg_t *btb, pfm_ita_pmd_reg_t *pmd16)

{

	int i, last;

	i    = (pmd16->pmd16_ita_reg.btbi_full) ? pmd16->pmd16_ita_reg.btbi_bbi : 0;

	last = pmd16->pmd16_ita_reg.btbi_bbi;

	safe_printf("btb_trace: i=%d last=%d bbi=%d full=%d\n", i, last,pmd16->pmd16_ita_reg.btbi_bbi, pmd16->pmd16_ita_reg.btbi_full);

	do {

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

		i = (i+1) % 8;

	} while (i != last);

}

static void

process_smpl_buffer(void)

{

	btb_hdr_t	*hdr;

	btb_entry_t	*ent;

	unsigned long pos;

	unsigned long smpl_entry = 0;

	pfm_ita_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 CPU:%d STAMP:0x%lx IIP:0x%016lx\n",

			smpl_entry++,

			ent->pid,

			ent->cpu,

			ent->tstamp,

			ent->ip);

		/*

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

		 */

		reg = (pfm_ita_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 (perfmonctl(id, PFM_RESTART,NULL, 0) == -1) {

		perror("PFM_RESTART");

		exit(1);

	}

}

int

main(void)

{

	int ret;

	int type = 0;

	pfmlib_input_param_t inp;

	pfmlib_output_param_t outp;

	pfmlib_ita_input_param_t ita_inp;

	pfarg_reg_t pd[NUM_PMDS];

	pfarg_reg_t pc[NUM_PMCS];

	btb_ctx_arg_t  ctx[1];

	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)

	 */

	if (pfm_initialize() != PFMLIB_SUCCESS) {

		fatal_error("Can't initialize library\n");

	}

	/*

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

	 */

	pfm_get_pmu_type(&type);

	if (type != PFMLIB_ITANIUM_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 = 0; /* set to 1 for debug */

	pfm_set_options(&pfmlib_options);

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

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

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

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

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

	/*

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

	 * of branches we want to capture. We are interesteed in all the mispredicted branches,

	 * therefore we program we set the various fields of the BTB config to:

	 */

	ita_inp.pfp_ita_btb.btb_used = 1;

	ita_inp.pfp_ita_btb.btb_tar = 0x1;

	ita_inp.pfp_ita_btb.btb_tm  = 0x2;

	ita_inp.pfp_ita_btb.btb_ptm = 0x3;

	ita_inp.pfp_ita_btb.btb_tac = 0x1;

	ita_inp.pfp_ita_btb.btb_bac = 0x1;

	ita_inp.pfp_ita_btb.btb_ppm = 0x3;

	ita_inp.pfp_ita_btb.btb_plm = PFM_PLM3;

	/*

	 * To count the number of occurence of this instruction, we must

	 * program a counting monitor with the IA64_TAGGED_INST_RETIRED_PMC8

	 * event.

	 */

	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, &ita_inp, &outp, NULL)) != PFMLIB_SUCCESS) {

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

	}

	 /*

	  * We initialize the format specific information.

	  * The format is identified by its UUID which must be copied

	  * into the ctx_buf_fmt_id field.

	  */

	memcpy(ctx[0].ctx_arg.ctx_smpl_buf_id, buf_fmt_id, sizeof(pfm_uuid_t));

	/*

	 * 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.

	 */

	ctx[0].buf_arg.buf_size = 8192;

	/*

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

	 */

	if (perfmonctl(0, PFM_CREATE_CONTEXT, ctx, 1) == -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));

	}

	printf("Sampling buffer mapped at %p\n", ctx[0].ctx_arg.ctx_smpl_vaddr);

	smpl_vaddr = ctx[0].ctx_arg.ctx_smpl_vaddr;

	/*

	 * extract our file descriptor

	 */

	id = ctx[0].ctx_arg.ctx_fd;

	/*

	 * 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;

	}

	/*

	 * the PMC controlling the event ALWAYS come first, that's why this loop

	 * is safe even when extra PMC are needed to support a particular event.

	 */

	for (i=0; i < inp.pfp_event_count; i++) {

		pd[i].reg_num   = pc[i].reg_num;

	}

	/*

	 * indicate we want notification when buffer is full

	 */

	pc[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       = (~0UL) - SMPL_PERIOD +1;

	pd[0].reg_long_reset  = (~0UL) - SMPL_PERIOD +1;

	pd[0].reg_short_reset = (~0UL) - SMPL_PERIOD +1;

	/*

	 * indicate PMD to collect in each sample

	 */

	pc[0].reg_smpl_pmds[0] = BTB_REGS_MASK;

	/*

	 * compute size of each sample: fixed-size header + all our BTB regs

	 */

	entry_size = sizeof(btb_entry_t)+(hweight64(BTB_REGS_MASK)<<3);

	/*

	 * 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.

	 */

	pc[0].reg_reset_pmds[0] = M_PMD(16);

	/*

	 * reset pmd16 (BTB index), short and long reset value are set to zero as well

	 *

	 * We use slot 1 of our pd[] array for this.

	 */

	pd[1].reg_num         = 16;

	pd[1].reg_value       = 0UL;

	/*

	 * Now program the registers

	 *

	 * We don't use the save variable to indicate the number of elements passed to

	 * the kernel because, as we said earlier, pc may contain more elements than

	 * the number of events we specified, i.e., contains more thann coutning monitors.

	 */

	if (perfmonctl(id, PFM_WRITE_PMCS, pc, outp.pfp_pmc_count) == -1) {

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

	}

	/*

	 * we use 2 = 1 for the branch_event + 1 for the reset of PMD16.

	 */

	if (perfmonctl(id, PFM_WRITE_PMDS, pd, 2) == -1) {

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

	}

	/*

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

	 */

	load_args.load_pid = getpid();

	if (perfmonctl(id, PFM_LOAD_CONTEXT, &load_args, 1) == -1) {

		fatal_error("perfmonctl error PFM_LOAD_CONTEXT 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

	 */

	close(id);

	return 0;

}