[PATCH] Ratelimit rewinds of sinks

[David Henningsson]

Allow max 10 rewinds in 200 ms in order to try to counteract the
eternal rewind issues still seen on low-end CPUs (e g Atom)

BugLink: http://bugs.launchpad.net/bugs/825709
Signed-off-by: David Henningsson <david.henningsson at canonical.com>
---
 src/pulsecore/sink.c |    8 ++++++++
 src/pulsecore/sink.h |    2 ++
 2 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/src/pulsecore/sink.c b/src/pulsecore/sink.c
index d97fb7e..2d006a5 100644
--- a/src/pulsecore/sink.c
+++ b/src/pulsecore/sink.c
@@ -332,6 +332,7 @@ pa_sink* pa_sink_new(
     s->thread_info.state = s->state;
     s->thread_info.rewind_nbytes = 0;
     s->thread_info.rewind_requested = FALSE;
+    PA_INIT_RATELIMIT(s->thread_info.rewind_limit, PA_USEC_PER_MSEC * 200, 10); /* max 10 rewinds in 200 ms */
     s->thread_info.max_rewind = 0;
     s->thread_info.max_request = 0;
     s->thread_info.requested_latency_valid = FALSE;
@@ -932,6 +933,13 @@ void pa_sink_process_rewind(pa_sink *s, size_t nbytes) {
         if (s->monitor_source && PA_SOURCE_IS_LINKED(s->monitor_source->thread_info.state))
             pa_source_process_rewind(s->monitor_source, nbytes);
     }
+
+    if (!pa_ratelimit_test(&s->thread_info.rewind_limit, PA_LOG_DEBUG)) {
+        pa_log_warn("Okay, I'm sick and tired of all this rewinding. I'm going to sleep for %lu ms!",
+            s->thread_info.rewind_limit.interval / PA_USEC_PER_MSEC);
+        usleep(s->thread_info.rewind_limit.interval);
+        pa_log_debug("Waking up.");
+    }
 }
 
 /* Called from IO thread context */
diff --git a/src/pulsecore/sink.h b/src/pulsecore/sink.h
index 0642dda..8c998e8 100644
--- a/src/pulsecore/sink.h
+++ b/src/pulsecore/sink.h
@@ -47,6 +47,7 @@ typedef struct pa_sink_volume_change pa_sink_volume_change;
 #include <pulsecore/queue.h>
 #include <pulsecore/thread-mq.h>
 #include <pulsecore/sink-input.h>
+#include <pulsecore/ratelimit.h>
 
 #define PA_MAX_INPUTS_PER_SINK 32
 
@@ -261,6 +262,7 @@ struct pa_sink {
         /* Maximum of what clients requested to rewind in this cycle */
         size_t rewind_nbytes;
         pa_bool_t rewind_requested;
+        pa_ratelimit rewind_limit;
 
         /* Both dynamic and fixed latencies will be clamped to this
          * range. */
-- 
1.7.5.4


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