Sample Midterm Solutions Flashcards
How is a new process created?
Is there a benefit of multithreading on 1 CPU?
If the kernel cannot see user-level signal masks, then how is a signal delivered to a user-level thread (where the signal can be handled)?
What is a flash server?
The Flash Web server combines the
high performance of single-process event-driven servers
on cached workloads with the performance of multi-
process and multi-threaded servers on disk-bound work-
loads.
What is (AMPED)
the event-driven approach of the SPED architecture
with multiple helper processes (or threads) that handle
blocking disk I/O operations.
Difference between MT and MP
The primary difference between the MP and the MT
architecture, however, is that all threads can share global
variables. The use of a single shared address space lends
itself easily to optimizations that rely on shared state.
Advantage of AMPED to SPED
The AMPED architecture strives to preserve the effi-
ciency of the SPED architecture on operations other than
disk reads, but avoids the performance problems suffered
by SPED due to inappropriate support for asynchronous
disk reads in many operating systems. AMPED achieves
this using only support that is widely available in modern
operating systems.
I
What are helpers in AMPED
.
The helper processes are responsible for performing
pathname translations and for bringing disk blocks into
memory. These processes a
Conclusions of Flash paper
- Flash nearly matches the performance of SPED servers
on cached workloads while simultaneously matching or
exceeding the performance of MP and MT servers on
disk-intensive workloads.
- Results also show that the Flash server’s performance
exceeds that of the Zeus Web server by up to 30%, and
it exceeds the performance of Apache by up to 50% on
real workloads. F
Bandwith results
Bandwidth results 2
Optimizations results
