Ticket #4242: myth_IOMultiplier_r14915.diff

libs/libmythtv/RingBuffer.cpp

@@ -42 +42 @@
 
 const uint RingBuffer::kBufferSize = 3 * 1024 * 1024;
 
-#define CHUNK 32768 /* readblocksize increments */
+#define DEF_CHUNK 32768 /* default readblocksize increments */
 
 #define PNG_MIN_SIZE   20 /* header plus one empty chunk */
 #define NUV_MIN_SIZE  204 /* header size? */
@@ -96 +96 @@
       readsallowed(false),      wantseek(false), setswitchtonext(false),
       rawbitrate(4000),         playspeed(1.0f),
       fill_threshold(65536),    fill_min(-1),
-      readblocksize(CHUNK),     wanttoread(0),
+      readblocksize(DEF_CHUNK), wanttoread(0),
       numfailures(0),           commserror(false),
       dvdPriv(NULL),            oldfile(false),
       livetvchain(NULL),        ignoreliveeof(false),
@@ -118 +118 @@
         return;
     }
 
+    int io_multiplier = gContext->GetNumSetting("ReadWriteMultiplier", 5);
+
+    read_chunk_size = (2<<(io_multiplier - 1)) * 1024;
+    max_read_size = 640 / (32 / (2<<(io_multiplier - 1))) * 1024;
+
+    VERBOSE(VB_GENERAL, LOC + QString("Using io multiplier %1, chunk/max = "
+                                                                     "%2/%3")
+                                                          .arg(io_multiplier)
+                                                          .arg(read_chunk_size)
+                                                          .arg(max_read_size));
+
     if (read_retries != (uint)-1)
         OpenFile(filename, read_retries);
 }
@@ -531 +542 @@
     pthread_rwlock_wrlock(&rwlock);
     wantseek       = false;
     readsallowed   = false;
-    readblocksize  = CHUNK;
+    readblocksize  = read_chunk_size;
 
     // loop without sleeping if the buffered data is less than this
-    fill_threshold = CHUNK * 2;
+    fill_threshold = read_chunk_size * 2;
     fill_min       = 1;
 
 #ifdef USING_FRONTEND
@@ -606 +617 @@
 void RingBuffer::ResetReadAhead(long long newinternal)
 {
     readAheadLock.lock();
-    readblocksize = CHUNK;
+    readblocksize = read_chunk_size;
     rbrpos = 0;
     rbwpos = 0;
     internalreadpos = newinternal;
@@ -720 +731 @@
 
     struct timeval lastread, now;
     gettimeofday(&lastread, NULL);
-    const int KB640 = 640*1024;
     int readtimeavg = 300;
     int readinterval;
 
     pausereadthread = false;
 
-    readAheadBuffer = new char[kBufferSize + KB640];
+    readAheadBuffer = new char[kBufferSize + max_read_size];
 
     ResetReadAhead(0);
     totfree = ReadBufFree();
@@ -777 +787 @@
 
             readtimeavg = (readtimeavg * 9 + readinterval) / 10;
 
-            if (readtimeavg < 200 && readblocksize < KB640)
+            if (readtimeavg < 200 && readblocksize < max_read_size)
             {
-                readblocksize += CHUNK;
+                readblocksize += read_chunk_size;
                 //VERBOSE(VB_PLAYBACK,
                 //    QString("Avg read interval was %1 msec. %2K block size")
                 //            .arg(readtimeavg).arg(readblocksize/1024));
                 readtimeavg = 300;
             }
-            else if (readtimeavg > 400 && readblocksize > CHUNK)
+            else if (readtimeavg > 400 && readblocksize > read_chunk_size)
             {
-                readblocksize -= CHUNK;
+                readblocksize -= read_chunk_size;
                 //VERBOSE(VB_PLAYBACK,
                 //    QString("Avg read interval was %1 msec. %2K block size")
                 //            .arg(readtimeavg).arg(readblocksize/1024));

libs/libmythtv/RingBuffer.h

@@ -126 +126 @@
     long long readpos;
     long long writepos;
 
+    int read_chunk_size;
+    int max_read_size;
+
     bool stopreads;
 
     mutable pthread_rwlock_t rwlock;

libs/libmythtv/ThreadedFileWriter.cpp

@@ -22 +22 @@
 #define LOC_ERR QString("TFW, Error: ")
 
 const uint ThreadedFileWriter::TFW_DEF_BUF_SIZE   = 2*1024*1024;
-const uint ThreadedFileWriter::TFW_MAX_WRITE_SIZE = TFW_DEF_BUF_SIZE / 4;
-const uint ThreadedFileWriter::TFW_MIN_WRITE_SIZE = TFW_DEF_BUF_SIZE / 32;
+const uint ThreadedFileWriter::TFW_MAX_WRITE_SIZE = TFW_DEF_BUF_SIZE / 
+                                                    (128 / (2<<(5-1)));
+const uint ThreadedFileWriter::TFW_MIN_WRITE_SIZE = TFW_DEF_BUF_SIZE /
+                                                    (1024 / (2<<(5-1)));
 
 /** \class ThreadedFileWriter
  *  \brief This class supports the writing of recordings to disk.
@@ -148 +150 @@
         bzero(buf, TFW_DEF_BUF_SIZE + 64);
 
         tfw_buf_size = TFW_DEF_BUF_SIZE;
-        tfw_min_write_size = TFW_MIN_WRITE_SIZE;
+        int io_multiplier = gContext->GetNumSetting("ReadWriteMultiplier", 5);
+
+        tfw_min_write_size = TFW_DEF_BUF_SIZE / (1024 / (2<<(io_multiplier - 1)));
+        tfw_max_write_size = TFW_DEF_BUF_SIZE / (128 / (2<<(io_multiplier - 1)));
+
+        VERBOSE(VB_RECORD, LOC + QString("Using io multiplier %1, "
+                                          "min/max = %2/%3")
+                                                     .arg(io_multiplier)
+                                                     .arg(tfw_min_write_size)
+                                                     .arg(tfw_max_write_size));
+
         pthread_create(&writer, NULL, boot_writer, this);
         pthread_create(&syncer, NULL, boot_syncer, this);
         return true;
@@ -364 +376 @@
            buffer is valid, and we try to write all of it at once which
            takes a long time. During this time, the other thread fills up
            the 10% that was free... */
-        size = (size > TFW_MAX_WRITE_SIZE) ? TFW_MAX_WRITE_SIZE : size;
+        size = (size > tfw_max_write_size) ? tfw_max_write_size : size;
 
         bool write_ok;
         if (ignore_writes)

libs/libmythtv/ThreadedFileWriter.h

@@ -48 +48 @@
     bool            in_dtor;
     bool            ignore_writes;
     long long       tfw_min_write_size;
+    long long       tfw_max_write_size;
 
     // buffer position state
     uint            rpos;    ///< points to end of data written to disk

programs/mythtv-setup/backendsettings.cpp

@@ -171 +171 @@
     return bs;
 }
 
+static GlobalSpinBox *ReadWriteMultiplier()
+{
+    GlobalSpinBox *bs = new GlobalSpinBox(
+        "ReadWriteMultiplier", 2, 6, 1);
+    bs->setLabel(QObject::tr("File read & write size multiplier"));
+    bs->setHelpText(QObject::tr("This fine tunes filesystem reads & writes "
+                    "for differently performing storage "
+                    "systems. Use caution when adjusting from the default of "
+                    "5 as this may negatively impact LiveTV and recordings."));
+    bs->setValue(5);
+    return bs;
+}
+
 static HostLineEdit *MiscStatusScript()
 {
     HostLineEdit *he = new HostLineEdit("MiscStatusScript");
@@ -760 +773 @@
     fm->addChild(DeletesFollowLinks());
     fm->addChild(TruncateDeletes());
     fm->addChild(HDRingbufferSize());
+    fm->addChild(ReadWriteMultiplier());
     group2->addChild(fm);
     VerticalConfigurationGroup* misc = new VerticalConfigurationGroup(false);
     misc->addChild(MiscStatusScript());