From 6cc9d67c6f682cf04eea2d6e64a252b63a7eccdf Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 1 Mar 2021 19:21:08 -0800 Subject: [PATCH] accel/tcg: Precompute curr_cflags into cpu->tcg_cflags MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The primary motivation is to remove a dozen insns along the fast-path in tb_lookup. As a byproduct, this allows us to completely remove parallel_cpus. Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson --- accel/tcg/cpu-exec.c | 3 --- accel/tcg/tcg-accel-ops-mttcg.c | 3 +-- accel/tcg/tcg-accel-ops-rr.c | 2 +- accel/tcg/tcg-accel-ops.c | 8 ++++++++ accel/tcg/tcg-accel-ops.h | 1 + accel/tcg/translate-all.c | 4 ---- include/exec/exec-all.h | 7 +------ include/hw/core/cpu.h | 2 ++ linux-user/main.c | 1 + linux-user/sh4/signal.c | 8 +++++--- linux-user/syscall.c | 18 ++++++++++-------- 11 files changed, 30 insertions(+), 27 deletions(-) diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 931da96c2b..bdfa036ac8 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -267,8 +267,6 @@ void cpu_exec_step_atomic(CPUState *cpu) mmap_unlock(); } - /* Since we got here, we know that parallel_cpus must be true. */ - parallel_cpus = false; cpu_exec_enter(cpu); /* execute the generated code */ trace_exec_tb(tb, pc); @@ -296,7 +294,6 @@ void cpu_exec_step_atomic(CPUState *cpu) * the execution. */ g_assert(cpu_in_exclusive_context(cpu)); - parallel_cpus = true; cpu->running = false; end_exclusive(); } diff --git a/accel/tcg/tcg-accel-ops-mttcg.c b/accel/tcg/tcg-accel-ops-mttcg.c index 42973fb062..847d2079d2 100644 --- a/accel/tcg/tcg-accel-ops-mttcg.c +++ b/accel/tcg/tcg-accel-ops-mttcg.c @@ -114,8 +114,7 @@ void mttcg_start_vcpu_thread(CPUState *cpu) char thread_name[VCPU_THREAD_NAME_SIZE]; g_assert(tcg_enabled()); - - parallel_cpus = (current_machine->smp.max_cpus > 1); + tcg_cpu_init_cflags(cpu, current_machine->smp.max_cpus > 1); cpu->thread = g_malloc0(sizeof(QemuThread)); cpu->halt_cond = g_malloc0(sizeof(QemuCond)); diff --git a/accel/tcg/tcg-accel-ops-rr.c b/accel/tcg/tcg-accel-ops-rr.c index 4a66055e0d..018b54c508 100644 --- a/accel/tcg/tcg-accel-ops-rr.c +++ b/accel/tcg/tcg-accel-ops-rr.c @@ -269,7 +269,7 @@ void rr_start_vcpu_thread(CPUState *cpu) static QemuThread *single_tcg_cpu_thread; g_assert(tcg_enabled()); - parallel_cpus = false; + tcg_cpu_init_cflags(cpu, false); if (!single_tcg_cpu_thread) { cpu->thread = g_malloc0(sizeof(QemuThread)); diff --git a/accel/tcg/tcg-accel-ops.c b/accel/tcg/tcg-accel-ops.c index 6144d9df87..6cdcaa2855 100644 --- a/accel/tcg/tcg-accel-ops.c +++ b/accel/tcg/tcg-accel-ops.c @@ -41,6 +41,14 @@ /* common functionality among all TCG variants */ +void tcg_cpu_init_cflags(CPUState *cpu, bool parallel) +{ + uint32_t cflags = cpu->cluster_index << CF_CLUSTER_SHIFT; + cflags |= parallel ? CF_PARALLEL : 0; + cflags |= icount_enabled() ? CF_USE_ICOUNT : 0; + cpu->tcg_cflags = cflags; +} + void tcg_cpus_destroy(CPUState *cpu) { cpu_thread_signal_destroyed(cpu); diff --git a/accel/tcg/tcg-accel-ops.h b/accel/tcg/tcg-accel-ops.h index 48130006de..6a5fcef889 100644 --- a/accel/tcg/tcg-accel-ops.h +++ b/accel/tcg/tcg-accel-ops.h @@ -17,5 +17,6 @@ void tcg_cpus_destroy(CPUState *cpu); int tcg_cpus_exec(CPUState *cpu); void tcg_handle_interrupt(CPUState *cpu, int mask); +void tcg_cpu_init_cflags(CPUState *cpu, bool parallel); #endif /* TCG_CPUS_H */ diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index 0b0bfd35ab..f32df8b240 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -224,7 +224,6 @@ static void *l1_map[V_L1_MAX_SIZE]; TCGContext tcg_init_ctx; __thread TCGContext *tcg_ctx; TBContext tb_ctx; -bool parallel_cpus; static void page_table_config_init(void) { @@ -1867,9 +1866,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu, cflags = (cflags & ~CF_COUNT_MASK) | 1; } - cflags &= ~CF_CLUSTER_MASK; - cflags |= cpu->cluster_index << CF_CLUSTER_SHIFT; - max_insns = cflags & CF_COUNT_MASK; if (max_insns == 0) { max_insns = CF_COUNT_MASK; diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index a262dd5804..6b036cae8f 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -513,8 +513,6 @@ struct TranslationBlock { uintptr_t jmp_dest[2]; }; -extern bool parallel_cpus; - /* Hide the qatomic_read to make code a little easier on the eyes */ static inline uint32_t tb_cflags(const TranslationBlock *tb) { @@ -524,10 +522,7 @@ static inline uint32_t tb_cflags(const TranslationBlock *tb) /* current cflags for hashing/comparison */ static inline uint32_t curr_cflags(CPUState *cpu) { - uint32_t cflags = deposit32(0, CF_CLUSTER_SHIFT, 8, cpu->cluster_index); - cflags |= parallel_cpus ? CF_PARALLEL : 0; - cflags |= icount_enabled() ? CF_USE_ICOUNT : 0; - return cflags; + return cpu->tcg_cflags; } /* TranslationBlock invalidate API */ diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index c005d3dc2d..c68bc3ba8a 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -282,6 +282,7 @@ struct qemu_work_item; * to a cluster this will be UNASSIGNED_CLUSTER_INDEX; otherwise it will * be the same as the cluster-id property of the CPU object's TYPE_CPU_CLUSTER * QOM parent. + * @tcg_cflags: Pre-computed cflags for this cpu. * @nr_cores: Number of cores within this CPU package. * @nr_threads: Number of threads within this CPU. * @running: #true if CPU is currently running (lockless). @@ -412,6 +413,7 @@ struct CPUState { /* TODO Move common fields from CPUArchState here. */ int cpu_index; int cluster_index; + uint32_t tcg_cflags; uint32_t halted; uint32_t can_do_io; int32_t exception_index; diff --git a/linux-user/main.c b/linux-user/main.c index 81f48ff54e..4f4746dce8 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -205,6 +205,7 @@ CPUArchState *cpu_copy(CPUArchState *env) /* Reset non arch specific state */ cpu_reset(new_cpu); + new_cpu->tcg_cflags = cpu->tcg_cflags; memcpy(new_env, env, sizeof(CPUArchState)); /* Clone all break/watchpoints. diff --git a/linux-user/sh4/signal.c b/linux-user/sh4/signal.c index cc89a48ff8..29c1ee30e6 100644 --- a/linux-user/sh4/signal.c +++ b/linux-user/sh4/signal.c @@ -82,9 +82,11 @@ static abi_ulong get_sigframe(struct target_sigaction *ka, return (sp - frame_size) & -8ul; } -/* Notice when we're in the middle of a gUSA region and reset. - Note that this will only occur for !parallel_cpus, as we will - translate such sequences differently in a parallel context. */ +/* + * Notice when we're in the middle of a gUSA region and reset. + * Note that this will only occur when #CF_PARALLEL is unset, as we + * will translate such sequences differently in a parallel context. + */ static void unwind_gusa(CPUSH4State *regs) { /* If the stack pointer is sufficiently negative, and we haven't diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 389ec09764..9522f603aa 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -6481,6 +6481,16 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp, /* Grab a mutex so that thread setup appears atomic. */ pthread_mutex_lock(&clone_lock); + /* + * If this is our first additional thread, we need to ensure we + * generate code for parallel execution and flush old translations. + * Do this now so that the copy gets CF_PARALLEL too. + */ + if (!(cpu->tcg_cflags & CF_PARALLEL)) { + cpu->tcg_cflags |= CF_PARALLEL; + tb_flush(cpu); + } + /* we create a new CPU instance. */ new_env = cpu_copy(env); /* Init regs that differ from the parent. */ @@ -6521,14 +6531,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp, sigprocmask(SIG_BLOCK, &sigmask, &info.sigmask); cpu->random_seed = qemu_guest_random_seed_thread_part1(); - /* If this is our first additional thread, we need to ensure we - * generate code for parallel execution and flush old translations. - */ - if (!parallel_cpus) { - parallel_cpus = true; - tb_flush(cpu); - } - ret = pthread_create(&info.thread, &attr, clone_func, &info); /* TODO: Free new CPU state if thread creation failed. */