From 2f5aa20635c77af9421799a74ae4d2f10ea98cea Mon Sep 17 00:00:00 2001
From: Jan David Mol <mol@astron.nl>
Date: Thu, 20 Jul 2017 10:09:12 +0000
Subject: [PATCH] Task #11059: Disable O_DIRECT as it provides abysmal
performance on the current CEP4 settings
---
RTCP/Cobalt/OutputProc/src/MSWriterFile.h | 27 ++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/RTCP/Cobalt/OutputProc/src/MSWriterFile.h b/RTCP/Cobalt/OutputProc/src/MSWriterFile.h
index dd82e4125a0..4a1476bc7a4 100644
--- a/RTCP/Cobalt/OutputProc/src/MSWriterFile.h
+++ b/RTCP/Cobalt/OutputProc/src/MSWriterFile.h
@@ -21,11 +21,32 @@
#ifndef LOFAR_STORAGE_MSWRITERFILE_H
#define LOFAR_STORAGE_MSWRITERFILE_H
+// O_DIRECT gave us bad performance on CEP4. Compare:
+/*
+
+root@cpu01 ~]# dd if=/dev/zero of=/data/test/throughput.dd bs=104857600 count=10 oflag=direct
+10+0 records in
+10+0 records out
+1048576000 bytes (1.0 GB) copied, 60.8431 s, 17.2 MB/s
+
+[root@cpu01 ~]# dd if=/dev/zero of=/data/test/throughput.dd bs=104857600 count=10
+10+0 records in
+10+0 records out
+1048576000 bytes (1.0 GB) copied, 0.879391 s, 1.2 GB/s
+
+*/
+//#define USE_O_DIRECT
+
+#ifdef USE_O_DIRECT
+#include "FastFileStream.h"
+#else
+#include <Stream/FileStream.h>
+#endif
+
#include <string>
#include <CoInterface/StreamableData.h>
#include "MSWriter.h"
-#include "FastFileStream.h"
namespace LOFAR
{
@@ -49,7 +70,11 @@ namespace LOFAR
virtual size_t getDataSize();
protected:
+#ifdef USE_O_DIRECT
FastFileStream itsFile;
+#else
+ FileStream itsFile;
+#endif
};
--
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