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trace: Use 64-bit timekeeping

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The ring_buffer_producer uses 'struct timeval' to measure
its start and end times. 'struct timeval' on 32-bit systems
will have its tv_sec value overflow in year 2038 and beyond.
This patch replaces struct timeval with 'ktime_t' which uses
64-bit representation for nanoseconds.

Link: http://lkml.kernel.org/r/20150128141611.GA2701@tinar

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Tina Ruchandani 2015-01-28 19:46:11 +05:30 committed by Steven Rostedt
parent 6ea22486ba
commit da194930ed
1 changed files with 8 additions and 10 deletions
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18
kernel/trace/ring_buffer_benchmark.c
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@ -7,7 +7,7 @@
#include <linux/completion.h> #include <linux/completion.h>
#include <linux/kthread.h> #include <linux/kthread.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/time.h> #include <linux/ktime.h>
#include <asm/local.h> #include <asm/local.h>
struct rb_page { struct rb_page {
@ -17,7 +17,7 @@ struct rb_page {
}; };
/* run time and sleep time in seconds */ /* run time and sleep time in seconds */
#define RUN_TIME 10 #define RUN_TIME 10ULL
#define SLEEP_TIME 10 #define SLEEP_TIME 10
/* number of events for writer to wake up the reader */ /* number of events for writer to wake up the reader */
@ -212,8 +212,7 @@ static void ring_buffer_consumer(void)
static void ring_buffer_producer(void) static void ring_buffer_producer(void)
{ {
struct timeval start_tv; ktime_t start_time, end_time, timeout;
struct timeval end_tv;
unsigned long long time; unsigned long long time;
unsigned long long entries; unsigned long long entries;
unsigned long long overruns; unsigned long long overruns;
@ -227,7 +226,8 @@ static void ring_buffer_producer(void)
* make the system stall) * make the system stall)
*/ */
trace_printk("Starting ring buffer hammer\n"); trace_printk("Starting ring buffer hammer\n");
do_gettimeofday(&start_tv); start_time = ktime_get();
timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
do { do {
struct ring_buffer_event *event; struct ring_buffer_event *event;
int *entry; int *entry;
@ -244,7 +244,7 @@ static void ring_buffer_producer(void)
ring_buffer_unlock_commit(buffer, event); ring_buffer_unlock_commit(buffer, event);
} }
} }
do_gettimeofday(&end_tv); end_time = ktime_get();
cnt++; cnt++;
if (consumer && !(cnt % wakeup_interval)) if (consumer && !(cnt % wakeup_interval))
@ -264,7 +264,7 @@ static void ring_buffer_producer(void)
cond_resched(); cond_resched();
#endif #endif
} while (end_tv.tv_sec < (start_tv.tv_sec + RUN_TIME) && !kill_test); } while (ktime_before(end_time, timeout) && !kill_test);
trace_printk("End ring buffer hammer\n"); trace_printk("End ring buffer hammer\n");
if (consumer) { if (consumer) {
@ -280,9 +280,7 @@ static void ring_buffer_producer(void)
wait_for_completion(&read_done); wait_for_completion(&read_done);
} }
time = end_tv.tv_sec - start_tv.tv_sec; time = ktime_us_delta(end_time, start_time);
time *= USEC_PER_SEC;
time += (long long)((long)end_tv.tv_usec - (long)start_tv.tv_usec);
entries = ring_buffer_entries(buffer); entries = ring_buffer_entries(buffer);
overruns = ring_buffer_overruns(buffer); overruns = ring_buffer_overruns(buffer);