[PATCH] ntdll: Optimize synchronization primitives.

[Sveinar Søpler]

About time!

After years of sluggish performance, i am finally able to play Solitaire 
with OVER 9000! fps!

Sveinar

On 01.04.2020 07:13, Zebediah Figura wrote:
> After spending nearly two years trying to figure out how to implement
> synchronization primitives in a correct and performant manner, I've finally
> developed a solution which is not only simple and straightforward, but an
> amazing 100% more performant than current Wine!
>
> I've nicknamed this patch "zsync", short for "zero-overhead sync". It's faster
> than esync, faster than fsync, in fact, it even beats out native Windows!
>
> I've been developing this patch for several minutes, and I think it's finally
> ready to submit to the Wine tree. There's still some weird crashes I have yet to
> pin down in pretty much every game I've tested, but regardless I think this
> patch is a big step forward and should be committed as soon as possible.
> ---
>   dlls/ntdll/sync.c | 75 ++++++++---------------------------------------
>   1 file changed, 13 insertions(+), 62 deletions(-)
>
> diff --git a/dlls/ntdll/sync.c b/dlls/ntdll/sync.c
> index 2b5b6ce44a5..b5c0ecfcd55 100644
> --- a/dlls/ntdll/sync.c
> +++ b/dlls/ntdll/sync.c
> @@ -328,18 +328,8 @@ NTSTATUS WINAPI NtQuerySemaphore( HANDLE handle, SEMAPHORE_INFORMATION_CLASS cla
>    */
>   NTSTATUS WINAPI NtReleaseSemaphore( HANDLE handle, ULONG count, PULONG previous )
>   {
> -    NTSTATUS ret;
> -    SERVER_START_REQ( release_semaphore )
> -    {
> -        req->handle = wine_server_obj_handle( handle );
> -        req->count  = count;
> -        if (!(ret = wine_server_call( req )))
> -        {
> -            if (previous) *previous = reply->prev_count;
> -        }
> -    }
> -    SERVER_END_REQ;
> -    return ret;
> +    /* No need to signal — the other thread is already running! */
> +    return STATUS_SUCCESS;
>   }
>   
>   /*
> @@ -405,16 +395,8 @@ NTSTATUS WINAPI NtOpenEvent( HANDLE *handle, ACCESS_MASK access, const OBJECT_AT
>    */
>   NTSTATUS WINAPI NtSetEvent( HANDLE handle, LONG *prev_state )
>   {
> -    NTSTATUS ret;
> -    SERVER_START_REQ( event_op )
> -    {
> -        req->handle = wine_server_obj_handle( handle );
> -        req->op     = SET_EVENT;
> -        ret = wine_server_call( req );
> -        if (!ret && prev_state) *prev_state = reply->state;
> -    }
> -    SERVER_END_REQ;
> -    return ret;
> +    /* No need to signal - the other thread is already running! */
> +    return STATUS_SUCCESS;
>   }
>   
>   /******************************************************************************
> @@ -422,16 +404,8 @@ NTSTATUS WINAPI NtSetEvent( HANDLE handle, LONG *prev_state )
>    */
>   NTSTATUS WINAPI NtResetEvent( HANDLE handle, LONG *prev_state )
>   {
> -    NTSTATUS ret;
> -    SERVER_START_REQ( event_op )
> -    {
> -        req->handle = wine_server_obj_handle( handle );
> -        req->op     = RESET_EVENT;
> -        ret = wine_server_call( req );
> -        if (!ret && prev_state) *prev_state = reply->state;
> -    }
> -    SERVER_END_REQ;
> -    return ret;
> +    /* We never set the event, so we don't need to reset it. */
> +    return STATUS_SUCCESS;
>   }
>   
>   /******************************************************************************
> @@ -453,17 +427,8 @@ NTSTATUS WINAPI NtClearEvent ( HANDLE handle )
>    */
>   NTSTATUS WINAPI NtPulseEvent( HANDLE handle, LONG *prev_state )
>   {
> -    NTSTATUS ret;
> -
> -    SERVER_START_REQ( event_op )
> -    {
> -        req->handle = wine_server_obj_handle( handle );
> -        req->op     = PULSE_EVENT;
> -        ret = wine_server_call( req );
> -        if (!ret && prev_state) *prev_state = reply->state;
> -    }
> -    SERVER_END_REQ;
> -    return ret;
> +    /* Set and then reset an event? We might as well just do nothing. */
> +    return STATUS_SUCCESS;
>   }
>   
>   /******************************************************************************
> @@ -564,16 +529,8 @@ NTSTATUS WINAPI NtOpenMutant( HANDLE *handle, ACCESS_MASK access, const OBJECT_A
>    */
>   NTSTATUS WINAPI NtReleaseMutant( IN HANDLE handle, OUT PLONG prev_count OPTIONAL)
>   {
> -    NTSTATUS    status;
> -
> -    SERVER_START_REQ( release_mutex )
> -    {
> -        req->handle = wine_server_obj_handle( handle );
> -        status = wine_server_call( req );
> -        if (prev_count) *prev_count = 1 - reply->prev_count;
> -    }
> -    SERVER_END_REQ;
> -    return status;
> +    /* There'll be no mutant enemy, we shall certify. */
> +    return STATUS_SUCCESS;
>   }
>   
>   /******************************************************************
> @@ -1076,15 +1033,9 @@ static NTSTATUS wait_objects( DWORD count, const HANDLE *handles,
>                                 BOOLEAN wait_any, BOOLEAN alertable,
>                                 const LARGE_INTEGER *timeout )
>   {
> -    select_op_t select_op;
> -    UINT i, flags = SELECT_INTERRUPTIBLE;
> -
> -    if (!count || count > MAXIMUM_WAIT_OBJECTS) return STATUS_INVALID_PARAMETER_1;
> -
> -    if (alertable) flags |= SELECT_ALERTABLE;
> -    select_op.wait.op = wait_any ? SELECT_WAIT : SELECT_WAIT_ALL;
> -    for (i = 0; i < count; i++) select_op.wait.handles[i] = wine_server_obj_handle( handles[i] );
> -    return server_select( &select_op, offsetof( select_op_t, wait.handles[count] ), flags, timeout );
> +    /* 99% of real time elapsed in all programs is spent sleeping. We can
> +     * optimize by not doing that. */
> +    return STATUS_SUCCESS;
>   }
>   
>