various updates

[pintos-anon] / sigcse2009 / racedt.tex

diff --git a/sigcse2009/racedt.tex b/sigcse2009/racedt.tex
index d5e28719d4460c42892af90c5e9222c047da0ffb..37cc78cfa52133654400744c18ef078205051dab 100644 (file)
--- a/sigcse2009/racedt.tex
+++ b/sigcse2009/racedt.tex
@@ -5,7 +5,7 @@ Data races and invalid memory accesses are some of the most common and
 difficult to debug errors that may occur in concurrent C code.
 We developed dynamic analysis tools that run on top of the QEMU
 system emulator~\cite{Bellard2005QEMU} to help detect these mistakes. 
-Since these tools do not require additional support from the Pintos kernel; 
+Since these tools do not require additional support from the Pintos kernel,
 students can use them without complicating their code.
 
 Data races are found by using a semaphore-aware modification of the RaceTrack algorithm~\cite{Yu2005RaceTrack}. 
@@ -18,7 +18,10 @@ call stacks for the racing threads is generated.
 Invalid memory accesses, such as a read from newly allocated but uninitialized data, are detected by
 tracking all memory accesses.  Heap allocation calls are instrumented to map a range of addresses as
 uninitialized. When data is written to a memory address, it is marked as initialized. If an address
-marked as uninitialized is read from, the error is reported and the address is marked as
-uninitialized to mask spurious reports. 
+marked as uninitialized is read from, an error is reported.
+%cfl: and the address is marked as uninitialized to mask spurious reports. 
 % More sophisticated analysis may be implemented in the future.
 
+Each of our tools presents students with one or more concrete backtraces that
+show where the error occurred, which not only helps students debug their code,
+but makes the concept of race conditions more concrete.