Permalink
Browse files

RingBuffer: Optimize readahead buffer to completely fill if readblock…

…size > totfree.

This allows the readahead buffer to fill if the readblocksize is greater than buffer free by temporarily reducing the read size to a size that will fit. With this change the buffers reach 99% for all videos.

Backports d950637 from master.
  • Loading branch information...
tralph committed Aug 12, 2011
1 parent c212ca8 commit 1cf65bccbd186fcfdb8d55e31232a8cfe6fdb1a3
Showing with 8 additions and 5 deletions.
  1. +8 −5 mythtv/libs/libmythtv/RingBuffer.cpp
@@ -1147,8 +1147,7 @@ void RingBuffer::run(void)
// These are conditions where we don't want to go through
// the loop if they are true.
- if (((totfree < readblocksize) && readsallowed) ||
- (ignorereadpos >= 0) || commserror || stopreads)
+ if ((ignorereadpos >= 0) || commserror || stopreads)
{
ignore_for_read_timing |=
(ignorereadpos >= 0) || commserror || stopreads;
@@ -1165,12 +1164,16 @@ void RingBuffer::run(void)
totfree = ReadBufFree();
}
+ const uint KB32 = 32*1024;
int read_return = -1;
- if (totfree >= readblocksize && !commserror &&
+ if (totfree >= KB32 && !commserror &&
!ateof && !setswitchtonext)
{
// limit the read size
- totfree = readblocksize;
+ if (readblocksize > totfree)
+ totfree = (int)(totfree / KB32) * KB32; // must be multiple of 32KB
+ else
+ totfree = readblocksize;
// adapt blocksize
gettimeofday(&now, NULL);
@@ -1205,7 +1208,7 @@ void RingBuffer::run(void)
readtimeavg = 225;
}
}
- ignore_for_read_timing = false;
+ ignore_for_read_timing = (totfree < readblocksize) ? true : false;
lastread = now;
rbwlock.lockForRead();

0 comments on commit 1cf65bc

Please sign in to comment.