A CIL Tutorial - Department of Computer Science - ETH Zürich

CHAPTER 10. ADDING A NEW KIND OF STATEMENT 84
../ciltut-lib/src/tut10.c
# define _GNU_SOURCE // Needed for RTLD_NEXT
# include // for uint64_t
# include // for pthread_create
# include // for RTLD_NEXT
# include
# include
# include
# include
We'll omit from the text most of the code for setting up the performance counters. You can nd it
in ciltut libc.c. The important thing to note about this code is that perf get cache refs() returns
the cumulative number of cache references performed by the calling thread, and perf get cache miss()
returns the cumulative number of those references that missed the cache.
For each thread we'll keep a stack of records that each record the cumulative number of cache
misses (start miss), the cumulative number of cache references (start refs), and the starting
time (start time) at the beginning of a cache report statement.
struct cache_stack_entry {
uint64_t start_miss;
uint64_t start_refs;
uint64_t start_time;
};
../ciltut-lib/src/tut10.c
# define MAX_CACHE_STACK_ENTRIES 256
struct cache_stack {
struct cache_stack_entry s[MAX_CACHE_STACK_ENTRIES];
int t;
};
Next, we set up the thread local storage for the stack, and a pointer to the top of the stack. Linux
supports gcc's thread storage modier, but other OS's might not, for example Mac OSX. Thus,
we'll just stick to using pthread setspecific and pthread getspecific for implementing thread
local storage. The CONSTRUCTOR attribute on init CS key ensures that the stack is initialized in
the rst thread of the program. Next, we'll ensure that each new thread also calls init CS key.