case-truncate: use cat for sparsefile to consume memory

The intent of "cp sparsefile /dev/null" is to fill page cache with
sparsefile's content, but since cp will recognize the src file
being sparse and skip doing any read of it but just writing zeros to
/dev/null, it kind of failed the purpose.

Fix this by using 'cat sparsefile > /dev/null'.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/case-truncate b/case-truncate
index 7d75f7b..b72f012 100755
--- a/case-truncate
+++ b/case-truncate
@@ -8,7 +8,7 @@
 for i in `seq $nr_task`
 do
 	create_sparse_file $SPARSE_FILE-$i $((mem / nr_task))
-	cp $SPARSE_FILE-$i /dev/null
+	cat $SPARSE_FILE-$i > /dev/null
 done
 
 t0=$(date +%s.%N)