/* * 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 * * 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 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 #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 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 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_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 (perfmonctl(id, PFM_RESTART,NULL, 0) == -1) { perror("PFM_RESTART"); exit(1); } } int main(void) { int ret; int type = 0; pfarg_reg_t pd[NUM_PMDS]; pfarg_reg_t pc[NUM_PMCS]; pfmlib_input_param_t inp; pfmlib_output_param_t outp; pfmlib_ita2_input_param_t ita2_inp; 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_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 = 0; /* set to 1 for debug */ pfm_set_options(&pfmlib_options); memset(pd, 0, sizeof(pd)); memset(ctx, 0, sizeof(ctx)); /* * 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 interesteed in all the mispredicted branches, * therefore we program we set the various fields of the BTB config to: */ ita2_inp.pfp_ita2_btb.btb_used = 1; ita2_inp.pfp_ita2_btb.btb_ds = 0; ita2_inp.pfp_ita2_btb.btb_tm = 0x3; ita2_inp.pfp_ita2_btb.btb_ptm = 0x3; ita2_inp.pfp_ita2_btb.btb_ppm = 0x3; ita2_inp.pfp_ita2_btb.btb_brt = 0x0; ita2_inp.pfp_ita2_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, &ita2_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; }