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mtd: tests: Use boottime

PATCH In review Abhilash Jindal 2 participants 2 messages Aug 11, 2015 – Nov 10, 2015 Memory technology devices (MTD)

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Abhilash Jindal

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PATCH 1/1 mtd: tests: Use boottime

Wall time obtained from do_gettimeofday is susceptible to sudden jumps due to user setting the time or due to NTP. Boot time is constantly increasing time better suited for comparing two timestamps.

Signed-off-by Abhilash Jindal <[email protected]>
---
 drivers/mtd/tests/speedtest.c   |    9 ++++-----
 drivers/mtd/tests/torturetest.c |    9 ++++-----
 2 files changed, 8 insertions(+), 10 deletions(-)
drivers/mtd/tests/speedtest.c +4 -5
index 5a6f31a..854b707 100644
@@ -49,7 +49,7 @@ static int pgsize;
 static int ebcnt;
 static int pgcnt;
 static int goodebcnt;
-static struct timeval start, finish;
+static ktime_t start, finish;
 
 static int multiblock_erase(int ebnum, int blocks)
 {

@@ -168,12 +168,12 @@ static int read_eraseblock_by_2pages(int ebnum)
 
 static inline void start_timing(void)
 {
-	do_gettimeofday(&start);
+	start = ktime_get_boottime();
 }
 
 static inline void stop_timing(void)
 {
-	do_gettimeofday(&finish);
+	finish = ktime_get_boottime();
 }
 
 static long calc_speed(void)

@@ -181,8 +181,7 @@ static long calc_speed(void)
 	uint64_t k;
 	long ms;
 
-	ms = (finish.tv_sec - start.tv_sec) * 1000 +
-	     (finish.tv_usec - start.tv_usec) / 1000;
+	ms = ktime_to_ms(ktime_sub(finish, start));
 	if (ms == 0)
 		return 0;
 	k = (uint64_t)goodebcnt * (mtd->erasesize / 1024) * 1000;
drivers/mtd/tests/torturetest.c +4 -5
index e5d6e6d..228023a 100644
@@ -79,18 +79,18 @@ static unsigned char *check_buf;
 static unsigned int erase_cycles;
 
 static int pgsize;
-static struct timeval start, finish;
+static ktime_t start, finish;
 
 static void report_corrupt(unsigned char *read, unsigned char *written);
 
 static inline void start_timing(void)
 {
-	do_gettimeofday(&start);
+	start = ktime_get_boottime();
 }
 
 static inline void stop_timing(void)
 {
-	do_gettimeofday(&finish);
+	finish = ktime_get_boottime();
 }
 
 /*

@@ -333,8 +333,7 @@ static int __init tort_init(void)
 			long ms;
 
 			stop_timing();
-			ms = (finish.tv_sec - start.tv_sec) * 1000 +
-			     (finish.tv_usec - start.tv_usec) / 1000;
+			ms = ktime_to_ms(ktime_sub(finish, start));
 			pr_info("%08u erase cycles done, took %lu "
 			       "milliseconds (%lu seconds)\n",
 			       erase_cycles, ms, ms / 1000);
Signature · 1 line
1.7.9.5
#1 lore raw

+ others

Quoted 5 lines · Abhilash Jindal

Wall time obtained from do_gettimeofday is susceptible to sudden jumps due to user setting the time or due to NTP. Boot time is constantly increasing time better suited for comparing two timestamps.

Signed-off-by Abhilash Jindal <[email protected]>

Sorry, didn't notice this one earlier. We've merged an alternative patch that uses ktime_get():

commit af30c0a00aa0d086a820c2ec75544c07611834d7

Author: Shraddha Barke <[email protected]>
Date:   Thu Oct 22 20:29:54 2015 +0530

mtd: tests: Replace timeval with ktime_t

Quoted 1 line

From reading the API description, it's not really clear to me if

ktime_get() includes NTP jumps or not.

In any case, if you still need this patch, please rebase on the latest -next.

Regards,
Brian

Quoted 82 lines
---
 drivers/mtd/tests/speedtest.c   |    9 ++++-----
 drivers/mtd/tests/torturetest.c |    9 ++++-----
 2 files changed, 8 insertions(+), 10 deletions(-)
drivers/mtd/tests/speedtest.c +4 -5
index 5a6f31a..854b707 100644
@@ -49,7 +49,7 @@ static int pgsize;
 static int ebcnt;
 static int pgcnt;
 static int goodebcnt;
-static struct timeval start, finish;
+static ktime_t start, finish;
 
 static int multiblock_erase(int ebnum, int blocks)
 {

@@ -168,12 +168,12 @@ static int read_eraseblock_by_2pages(int ebnum)
 
 static inline void start_timing(void)
 {
-	do_gettimeofday(&start);
+	start = ktime_get_boottime();
 }
 
 static inline void stop_timing(void)
 {
-	do_gettimeofday(&finish);
+	finish = ktime_get_boottime();
 }
 
 static long calc_speed(void)

@@ -181,8 +181,7 @@ static long calc_speed(void)
 	uint64_t k;
 	long ms;
 
-	ms = (finish.tv_sec - start.tv_sec) * 1000 +
-	     (finish.tv_usec - start.tv_usec) / 1000;
+	ms = ktime_to_ms(ktime_sub(finish, start));
 	if (ms == 0)
 		return 0;
 	k = (uint64_t)goodebcnt * (mtd->erasesize / 1024) * 1000;
drivers/mtd/tests/torturetest.c +4 -5
index e5d6e6d..228023a 100644
@@ -79,18 +79,18 @@ static unsigned char *check_buf;
 static unsigned int erase_cycles;
 
 static int pgsize;
-static struct timeval start, finish;
+static ktime_t start, finish;
 
 static void report_corrupt(unsigned char *read, unsigned char *written);
 
 static inline void start_timing(void)
 {
-	do_gettimeofday(&start);
+	start = ktime_get_boottime();
 }
 
 static inline void stop_timing(void)
 {
-	do_gettimeofday(&finish);
+	finish = ktime_get_boottime();
 }
 
 /*

@@ -333,8 +333,7 @@ static int __init tort_init(void)
 			long ms;
 
 			stop_timing();
-			ms = (finish.tv_sec - start.tv_sec) * 1000 +
-			     (finish.tv_usec - start.tv_usec) / 1000;
+			ms = ktime_to_ms(ktime_sub(finish, start));
 			pr_info("%08u erase cycles done, took %lu "
 			       "milliseconds (%lu seconds)\n",
 			       erase_cycles, ms, ms / 1000);
Signature · 1 line
1.7.9.5