/* * 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 * * 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 #include #include #include #include #include #include #include #include #include #include #include #include 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) /* * We use a small buffer size to exercise the overflow handler */ #define SMPL_BUF_NENTRIES 64 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 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 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_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 (pfm_restart(id) == -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_pmr_t pc[NUM_PMCS]; pfarg_pmd_attr_t pd[NUM_PMDS]; smpl_arg_t buf_arg; 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_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(pc, 0, sizeof(pc)); memset(&buf_arg, 0, sizeof(buf_arg)); 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)); /* * 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 session */ id = pfm_create(PFM_FL_SMPL_FMT, NULL, "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("cannot create session %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 * * 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 (pfm_write(id, 0, PFM_RW_PMC, pc, outp.pfp_pmc_count * sizeof(*pc)) == -1) fatal_error("pfm_write error errno %d\n",errno); if (pfm_write(id, 0, PFM_RW_PMD_ATTR, pd, outp.pfp_pmd_count * sizeof(*pd)) == -1) fatal_error("pfm_write(PMD) error errno %d\n",errno); /* * now attach session */ if (pfm_attach(id, 0, getpid()) == -1) fatal_error("pfm_attach 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. */ if (pfm_set_state(id, 0, PFM_ST_START)) fatal_error("pfm_set_state error errno %d\n",errno); do_test(100000); if (pfm_set_state(id, 0, PFM_ST_STOP)) fatal_error("pfm_set_state error errno %d\n",errno); /* * 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; }