From c165408779ae3a5aceddc8603471b1c20e58fcae Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Cl=C3=A9ment=20L=C3=A9ger?= Date: Tue, 18 Jun 2024 13:26:45 +0200 Subject: target/riscv: fix instructions count handling in icount mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When icount is enabled, rather than returning the virtual CPU time, we should return the instruction count itself. Add an instructions bool parameter to get_ticks() to correctly return icount_get_raw() when icount_enabled() == 1 and instruction count is queried. This will modify the existing behavior which was returning an instructions count close to the number of cycles (CPI ~= 1). Signed-off-by: Clément Léger Reviewed-by: Atish Patra Message-ID: <20240618112649.76683-1-cleger@rivosinc.com> Signed-off-by: Alistair Francis --- target/riscv/csr.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/target/riscv/csr.c b/target/riscv/csr.c index 6f15612..432c59d 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -762,14 +762,18 @@ static RISCVException write_vcsr(CPURISCVState *env, int csrno, } /* User Timers and Counters */ -static target_ulong get_ticks(bool shift) +static target_ulong get_ticks(bool shift, bool instructions) { int64_t val; target_ulong result; #if !defined(CONFIG_USER_ONLY) if (icount_enabled()) { - val = icount_get(); + if (instructions) { + val = icount_get_raw(); + } else { + val = icount_get(); + } } else { val = cpu_get_host_ticks(); } @@ -804,14 +808,14 @@ static RISCVException read_timeh(CPURISCVState *env, int csrno, static RISCVException read_hpmcounter(CPURISCVState *env, int csrno, target_ulong *val) { - *val = get_ticks(false); + *val = get_ticks(false, (csrno == CSR_INSTRET)); return RISCV_EXCP_NONE; } static RISCVException read_hpmcounterh(CPURISCVState *env, int csrno, target_ulong *val) { - *val = get_ticks(true); + *val = get_ticks(true, (csrno == CSR_INSTRETH)); return RISCV_EXCP_NONE; } @@ -875,11 +879,11 @@ static RISCVException write_mhpmcounter(CPURISCVState *env, int csrno, int ctr_idx = csrno - CSR_MCYCLE; PMUCTRState *counter = &env->pmu_ctrs[ctr_idx]; uint64_t mhpmctr_val = val; + bool instr = riscv_pmu_ctr_monitor_instructions(env, ctr_idx); counter->mhpmcounter_val = val; - if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) || - riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) { - counter->mhpmcounter_prev = get_ticks(false); + if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) || instr) { + counter->mhpmcounter_prev = get_ticks(false, instr); if (ctr_idx > 2) { if (riscv_cpu_mxl(env) == MXL_RV32) { mhpmctr_val = mhpmctr_val | @@ -902,12 +906,12 @@ static RISCVException write_mhpmcounterh(CPURISCVState *env, int csrno, PMUCTRState *counter = &env->pmu_ctrs[ctr_idx]; uint64_t mhpmctr_val = counter->mhpmcounter_val; uint64_t mhpmctrh_val = val; + bool instr = riscv_pmu_ctr_monitor_instructions(env, ctr_idx); counter->mhpmcounterh_val = val; mhpmctr_val = mhpmctr_val | (mhpmctrh_val << 32); - if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) || - riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) { - counter->mhpmcounterh_prev = get_ticks(true); + if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) || instr) { + counter->mhpmcounterh_prev = get_ticks(true, instr); if (ctr_idx > 2) { riscv_pmu_setup_timer(env, mhpmctr_val, ctr_idx); } @@ -926,6 +930,7 @@ static RISCVException riscv_pmu_read_ctr(CPURISCVState *env, target_ulong *val, counter->mhpmcounter_prev; target_ulong ctr_val = upper_half ? counter->mhpmcounterh_val : counter->mhpmcounter_val; + bool instr = riscv_pmu_ctr_monitor_instructions(env, ctr_idx); if (get_field(env->mcountinhibit, BIT(ctr_idx))) { /* @@ -946,9 +951,8 @@ static RISCVException riscv_pmu_read_ctr(CPURISCVState *env, target_ulong *val, * The kernel computes the perf delta by subtracting the current value from * the value it initialized previously (ctr_val). */ - if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) || - riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) { - *val = get_ticks(upper_half) - ctr_prev + ctr_val; + if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) || instr) { + *val = get_ticks(upper_half, instr) - ctr_prev + ctr_val; } else { *val = ctr_val; } -- cgit v1.1