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accel/tcg: Precompute curr_cflags into cpu->tcg_cflags

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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 <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2021-03-01 19:21:08 -08:00
parent 872ebd884d
commit 6cc9d67c6f
11 changed files with 30 additions and 27 deletions
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18
linux-user/syscall.c
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@ -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. */