Understanding the reasons why multi-threaded applications do not
achieve perfect scaling on modern multicore hardware
is challenging. Furthermore, more and more modern programs are written in managed
languages, which have extra service threads (e.g., to perform memory
management), which may retard scalability and complicate performance analysis. In this
paper, we extend speedup stacks, a previously-presented visualization tool
to analyze multi-threaded program
scalability, to managed applications.
Speedup stacks are comprehensive bar
graphs that break down an application's execution to explain the main causes of
sublinear speedup, i.e., when some threads
are not allowing the application to progress, and
thus increasing the execution time.

We not only expand speedup stacks to analyze how the managed language's service threads affect overall scalability, but also implement speedup stacks while running on native hardware.
We monitor the application and service threads' scheduling behavior using light-weight OS kernel modules, incurring under 1% overhead
running unmodified Java benchmarks. We add two performance delimiters targeting managed applications: garbage collection and main initialization activities.
We analyze the scalability limitations of these benchmarks and the impact of using both a stop-the-world and a concurrent garbage collector with speedup stacks.
Our visualization tool facilitates the
identification of scalability bottlenecks both between application threads and of service threads, pointing developers to whether optimization should be focused on the language runtime or the application. Speedup stacks provide better program
understanding for both program and system designers, which can help
optimize multicore processor performance.
Original languageEnglish
Title of host publicationIEEE International Symposium on Performance Analysis of Systems and Software
Number of pages10
ISBN (Electronic)978-1-5386-3890-3
ISBN (Print)978-1-5386-3889-7 , 978-1-5386-3891-0
StatePublished - Apr 2017
EventIEEE International Symposium on Performance Analysis of Systems and Software - Santa Rosa, California, United States
Duration: 24 Apr 201725 Apr 2017


ConferenceIEEE International Symposium on Performance Analysis of Systems and Software
Abbreviated titleISPASS
CountryUnited States
Internet address

ID: 30523822