Avoid using pa_stream_begin_write with PulseAudio

It seems to actually have a negative performance impact when the system is
under load. Without having actual measurements for any potential benefits,
simply go with the recommended (and previous fallback) method of allocating
space for the write and passing the free method.

Ideally some kind of ring buffer could be used, so rather than constantly
allocating and freeing blocks of memory, it uses the same memory over again
with the callback marking each one as reusable. Unfortunately the callback
isn't given much information to work with, and the update size (minreq) can
potentially change during playback, which complicates things.

1 files changed, 9 insertions, 23 deletions

diff --git a/Alc/backends/pulseaudio.c b/Alc/backends/pulseaudio.c
index 96794e20..be785707 100644
--- a/Alc/backends/pulseaudio.c
+++ b/Alc/backends/pulseaudio.c
@@ -833,6 +833,9 @@ static int ALCpulsePlayback_mixerProc(void *ptr)
     while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
           ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
+        void *buf;
+        int ret;
+
         len = pa_stream_writable_size(self->stream);
         if(len < 0)
         {
@@ -863,33 +866,16 @@ static int ALCpulsePlayback_mixerProc(void *ptr)
             pa_threaded_mainloop_wait(self->loop);
             continue;
         }
-        len -= len%self->attr.minreq;
 
-        while(len > 0)
-        {
-            size_t newlen = len;
-            int ret;
-            void *buf;
-            pa_free_cb_t free_func = NULL;
+        len -= len%self->attr.minreq;
+        len -= len%frame_size;
 
-            if(pa_stream_begin_write(self->stream, &buf, &newlen) < 0)
-            {
-                buf = pa_xmalloc(newlen);
-                free_func = pa_xfree;
-            }
+        buf = pa_xmalloc(len);
 
-            newlen /= frame_size;
-            aluMixData(device, buf, newlen);
+        aluMixData(device, buf, len/frame_size);
 
-            newlen *= frame_size;
-            ret = pa_stream_write(self->stream, buf, newlen, free_func, 0, PA_SEEK_RELATIVE);
-            if(ret != PA_OK)
-            {
-                ERR("Failed to write to stream: %d, %s\n", ret, pa_strerror(ret));
-                break;
-            }
-            len -= newlen;
-        }
+        ret = pa_stream_write(self->stream, buf, len, pa_xfree, 0, PA_SEEK_RELATIVE);
+        if(ret != PA_OK) ERR("Failed to write to stream: %d, %s\n", ret, pa_strerror(ret));
     }
     pa_threaded_mainloop_unlock(self->loop);