From patchwork Fri Apr  6 03:48:19 2007
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Date: Thu, 5 Apr 2007 20:48:19 -0700
From: Stone <syphyr@gmail.com>
To: "VDR Mailing List" <vdr@linuxtv.org>
Subject: Re: [vdr] [PATCH] limit streamdev client's ringbuffer timeouts to
	more sane values
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On 4/5/07, Artur Skawina <art_k@o2.pl> wrote:
>
> Well, the streamdev-client reads data from a ringbuffer and when there
> isn't anything
> to read it tries to sleep for 1us and loops. This wasn't a problem when
> the timer
> resolution was in the 1000..10000us range (1000..100Hz); the usleep(1)
> call slept
> for one or more milliseconds.
> With the high-res timers in kernel 2.6.21+ usleep(1) is no longer treated
> as
> usleep(10000) and the streamdev client is almost unusable; it uses most of
> the cpu
> and causes hundreds of thousands context switches per second.
> This gets rid of the almost-busy-loop.



How about his approach?

--- streamdev/client/filter.c.orig      2007-04-05 20:45:04.000000000 -0700
+++ streamdev/client/filter.c   2007-04-05 20:45:44.000000000 -0700
@@ -135,7 +135,7 @@
                        }
                        m_RingBuffer->Del(TS_SIZE);
                } else
-                       usleep(1);
+                       cCondWait::SleepMs(1);
        }
 }