On 23/08/2015 17:23, Emilio G. Cota wrote:
> On some parallel workloads this gives up to a 15% speed improvement.
>
> Signed-off-by: Emilio G. Cota <c...@braap.org>
> ---
> include/qemu/thread-posix.h | 47 ++++++++++++++++++++++++++++++++++++++++++
> include/qemu/thread.h | 6 ------
> util/qemu-thread-posix.c | 50
> +++++----------------------------------------
> 3 files changed, 52 insertions(+), 51 deletions(-)
>
> diff --git a/include/qemu/thread-posix.h b/include/qemu/thread-posix.h
> index 8ce8f01..7d3a9f1 100644
> --- a/include/qemu/thread-posix.h
> +++ b/include/qemu/thread-posix.h
> @@ -37,4 +37,51 @@ struct QemuThread {
> pthread_t thread;
> };
>
> +void qemu_spin_error_exit(int err, const char *msg);
> +
> +static inline void qemu_spin_init(QemuSpin *spin)
> +{
> + int err;
> +
> + err = pthread_spin_init(&spin->lock, 0);
> + if (err) {
> + qemu_spin_error_exit(err, __func__);
> + }
> +}
> +
> +static inline void qemu_spin_destroy(QemuSpin *spin)
> +{
> + int err;
> +
> + err = pthread_spin_destroy(&spin->lock);
> + if (err) {
> + qemu_spin_error_exit(err, __func__);
> + }
> +}
> +
> +static inline void qemu_spin_lock(QemuSpin *spin)
> +{
> + int err;
> +
> + err = pthread_spin_lock(&spin->lock);
> + if (err) {
> + qemu_spin_error_exit(err, __func__);
> + }
> +}
> +
> +static inline int qemu_spin_trylock(QemuSpin *spin)
> +{
> + return pthread_spin_trylock(&spin->lock);
> +}
> +
> +static inline void qemu_spin_unlock(QemuSpin *spin)
> +{
> + int err;
> +
> + err = pthread_spin_unlock(&spin->lock);
> + if (err) {
> + qemu_spin_error_exit(err, __func__);
> + }
> +}
> +
> #endif
> diff --git a/include/qemu/thread.h b/include/qemu/thread.h
> index f5d1259..003daab 100644
> --- a/include/qemu/thread.h
> +++ b/include/qemu/thread.h
> @@ -26,12 +26,6 @@ void qemu_mutex_lock(QemuMutex *mutex);
> int qemu_mutex_trylock(QemuMutex *mutex);
> void qemu_mutex_unlock(QemuMutex *mutex);
>
> -void qemu_spin_init(QemuSpin *spin);
> -void qemu_spin_destroy(QemuSpin *spin);
> -void qemu_spin_lock(QemuSpin *spin);
> -int qemu_spin_trylock(QemuSpin *spin);
> -void qemu_spin_unlock(QemuSpin *spin);
> -
> void qemu_cond_init(QemuCond *cond);
> void qemu_cond_destroy(QemuCond *cond);
>
> diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
> index 224bacc..04dae0f 100644
> --- a/util/qemu-thread-posix.c
> +++ b/util/qemu-thread-posix.c
> @@ -48,6 +48,11 @@ static void error_exit(int err, const char *msg)
> abort();
> }
>
> +void qemu_spin_error_exit(int err, const char *msg)
> +{
> + error_exit(err, msg);
> +}
> +
> void qemu_mutex_init(QemuMutex *mutex)
> {
> int err;
> @@ -89,51 +94,6 @@ void qemu_mutex_unlock(QemuMutex *mutex)
> error_exit(err, __func__);
> }
>
> -void qemu_spin_init(QemuSpin *spin)
> -{
> - int err;
> -
> - err = pthread_spin_init(&spin->lock, 0);
> - if (err) {
> - error_exit(err, __func__);
> - }
> -}
> -
> -void qemu_spin_destroy(QemuSpin *spin)
> -{
> - int err;
> -
> - err = pthread_spin_destroy(&spin->lock);
> - if (err) {
> - error_exit(err, __func__);
> - }
> -}
> -
> -void qemu_spin_lock(QemuSpin *spin)
> -{
> - int err;
> -
> - err = pthread_spin_lock(&spin->lock);
> - if (err) {
> - error_exit(err, __func__);
> - }
> -}
> -
> -int qemu_spin_trylock(QemuSpin *spin)
> -{
> - return pthread_spin_trylock(&spin->lock);
> -}
> -
> -void qemu_spin_unlock(QemuSpin *spin)
> -{
> - int err;
> -
> - err = pthread_spin_unlock(&spin->lock);
> - if (err) {
> - error_exit(err, __func__);
> - }
> -}
> -
> void qemu_cond_init(QemuCond *cond)
> {
> int err;
>
Applied, but in the end the spinlock will probably simply use a simple
test-and-test-and-set lock, or an MCS lock. There is no need to use
pthreads for this.
Paolo
