diff options
| author | Jan Kiszka <jan.kiszka@siemens.com> | 2017-02-23 18:29:11 +0000 |
|---|---|---|
| committer | Alex Bennée <alex.bennee@linaro.org> | 2017-02-24 10:32:45 +0000 |
| commit | 8d04fb55dec381bc5105cb47f29d918e579e8cbd (patch) | |
| tree | 279eb632e33d57c869bae0b70c6261af5d0e854a /hw/i386/kvmvapic.c | |
| parent | 791158d93b27f22a17c2ada06621831d54f09a2c (diff) | |
tcg: drop global lock during TCG code execution
This finally allows TCG to benefit from the iothread introduction: Drop
the global mutex while running pure TCG CPU code. Reacquire the lock
when entering MMIO or PIO emulation, or when leaving the TCG loop.
We have to revert a few optimization for the current TCG threading
model, namely kicking the TCG thread in qemu_mutex_lock_iothread and not
kicking it in qemu_cpu_kick. We also need to disable RAM block
reordering until we have a more efficient locking mechanism at hand.
Still, a Linux x86 UP guest and my Musicpal ARM model boot fine here.
These numbers demonstrate where we gain something:
20338 jan 20 0 331m 75m 6904 R 99 0.9 0:50.95 qemu-system-arm
20337 jan 20 0 331m 75m 6904 S 20 0.9 0:26.50 qemu-system-arm
The guest CPU was fully loaded, but the iothread could still run mostly
independent on a second core. Without the patch we don't get beyond
32206 jan 20 0 330m 73m 7036 R 82 0.9 1:06.00 qemu-system-arm
32204 jan 20 0 330m 73m 7036 S 21 0.9 0:17.03 qemu-system-arm
We don't benefit significantly, though, when the guest is not fully
loading a host CPU.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Message-Id: <1439220437-23957-10-git-send-email-fred.konrad@greensocs.com>
[FK: Rebase, fix qemu_devices_reset deadlock, rm address_space_* mutex]
Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
[EGC: fixed iothread lock for cpu-exec IRQ handling]
Signed-off-by: Emilio G. Cota <cota@braap.org>
[AJB: -smp single-threaded fix, clean commit msg, BQL fixes]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
[PM: target-arm changes]
Acked-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'hw/i386/kvmvapic.c')
| -rw-r--r-- | hw/i386/kvmvapic.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c index 7135633863..82a49556af 100644 --- a/hw/i386/kvmvapic.c +++ b/hw/i386/kvmvapic.c @@ -457,8 +457,8 @@ static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip) resume_all_vcpus(); if (!kvm_enabled()) { - /* tb_lock will be reset when cpu_loop_exit_noexc longjmps - * back into the cpu_exec loop. */ + /* Both tb_lock and iothread_mutex will be reset when + * longjmps back into the cpu_exec loop. */ tb_lock(); tb_gen_code(cs, current_pc, current_cs_base, current_flags, 1); cpu_loop_exit_noexc(cs); |