Flush .hp file at the end of each sample
|Reported by:||akio||Owned by:|
|Type of failure:||None/Unknown||Difficulty:||Unknown|
|Test Case:||Blocked By:|
Tools like hp2any-graph reads a .hp file as it's being written to. However writing to .hp files is currently block-buffered, causing a delay until the latest sample can be read. The attached patch adds a call to fflush every time a complete sample is written.