[PATCH] [dvbv5-scan] wait no more than timeout when scanning

[PATCH] [dvbv5-scan] wait no more than timeout when scanning

[Abylay Ospan]

some frontends (mentioned on lgdt3306a) wait timeout inside code like:
for (i = 20; i > 0; i--) {
  msleep(50);

If there is no-LOCK then dvbv5-scan spent a lot of time (doing 40x calls).
This patch introduce timeout which 4 sec * multiply. So we do not wait more
than 4 sec (or so) if no-LOCK.

Signed-off-by: Abylay Ospan <aospan@netup.ru>
---
 utils/dvb/dvbv5-scan.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/utils/dvb/dvbv5-scan.c b/utils/dvb/dvbv5-scan.c
index 689bc0b..1fc33d7 100644
--- a/utils/dvb/dvbv5-scan.c
+++ b/utils/dvb/dvbv5-scan.c
@@ -182,12 +182,23 @@ static int print_frontend_stats(struct arguments *args,
 	return 0;
 }
 
+/* return timestamp in msec */
+uint64_t get_timestamp()
+{
+	struct timeval now;
+	gettimeofday(&now, 0);
+	return now.tv_sec * 1000 + now.tv_usec/1000;
+}
+
 static int check_frontend(void *__args,
 			  struct dvb_v5_fe_parms *parms)
 {
 	struct arguments *args = __args;
 	int rc, i;
 	fe_status_t status;
+	uint64_t start = get_timestamp();
+	/* msec timeout by default 4 sec * multiply */ 
+	uint64_t timeout = args->timeout_multiply * 4 * 1000;
 
 	args->n_status_lines = 0;
 	for (i = 0; i < args->timeout_multiply * 40; i++) {
@@ -203,6 +214,10 @@ static int check_frontend(void *__args,
 		print_frontend_stats(args, parms);
 		if (status & FE_HAS_LOCK)
 			break;
+
+		if ((get_timestamp() - start) > timeout)
+			break;
+
 		usleep(100000);
 	};
 
-- 
2.7.4

Re: [PATCH] [dvbv5-scan] wait no more than timeout when scanning

[Mauro Carvalho Chehab]

Hi Abylay,

Em Fri, 22 Jul 2016 13:54:37 -0400
Abylay Ospan <aospan@netup.ru> escreveu:

> some frontends (mentioned on lgdt3306a) wait timeout inside code like:
> for (i = 20; i > 0; i--) {
>   msleep(50);
> 
> If there is no-LOCK then dvbv5-scan spent a lot of time (doing 40x calls).
> This patch introduce timeout which 4 sec * multiply. So we do not wait more
> than 4 sec (or so) if no-LOCK.
> 
> Signed-off-by: Abylay Ospan <aospan@netup.ru>
> ---
>  utils/dvb/dvbv5-scan.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/utils/dvb/dvbv5-scan.c b/utils/dvb/dvbv5-scan.c
> index 689bc0b..1fc33d7 100644
> --- a/utils/dvb/dvbv5-scan.c
> +++ b/utils/dvb/dvbv5-scan.c
> @@ -182,12 +182,23 @@ static int print_frontend_stats(struct arguments *args,
>  	return 0;
>  }
>  
> +/* return timestamp in msec */
> +uint64_t get_timestamp()
> +{
> +	struct timeval now;
> +	gettimeofday(&now, 0);
> +	return now.tv_sec * 1000 + now.tv_usec/1000;

This is not good, as gettimeofday() is not monotonic, and may be affected
by clock adjustments.

IMHO, the best would be to adjust the do_timeout() to handle
args->timeout_multiply.

Regards,
Mauro

> +}
> +
>  static int check_frontend(void *__args,
>  			  struct dvb_v5_fe_parms *parms)
>  {
>  	struct arguments *args = __args;
>  	int rc, i;
>  	fe_status_t status;
> +	uint64_t start = get_timestamp();
> +	/* msec timeout by default 4 sec * multiply */ 
> +	uint64_t timeout = args->timeout_multiply * 4 * 1000;
>  
>  	args->n_status_lines = 0;
>  	for (i = 0; i < args->timeout_multiply * 40; i++) {
> @@ -203,6 +214,10 @@ static int check_frontend(void *__args,
>  		print_frontend_stats(args, parms);
>  		if (status & FE_HAS_LOCK)
>  			break;
> +
> +		if ((get_timestamp() - start) > timeout)
> +			break;
> +
>  		usleep(100000);

It would also make sense to remove the usleep here and
use something else that would be checking timeout_flag,
like:

	for (i = 1; i < 100; i++) {
		if (timeout_flag)
			break;
		usleep(1000);
	}


-- 
Thanks,
Mauro

Re: [PATCH] [dvbv5-scan] wait no more than timeout when scanning

[Abylay Ospan]

Hi Mauro,

I have checked 'do_timeout' - it's bit different that we want. I just
updated patch to use 'clock_gettime(CLOCK_MONOTONIC' to avoid
timestamps 'rollup'.
Hope it's ok. The problem is really annoying because scanning takes a
lot of time.
Without this patch command 'dvbv5-scan
us-ATSC-center-frequencies-8VSB' takes about 2 hours.
with patch it takes just 6min 45sec - which better but has a room for
optimization inside lgdt3306a.c driver - it waits about 4 sec for each
read status which I think is too long. If we have signal we should
lock in about 100-500 msec. I will check this question later.

2016-07-22 15:18 GMT-04:00 Mauro Carvalho Chehab <mchehab@osg.samsung.com>:
> Hi Abylay,
>
> Em Fri, 22 Jul 2016 13:54:37 -0400
> Abylay Ospan <aospan@netup.ru> escreveu:
>
>> some frontends (mentioned on lgdt3306a) wait timeout inside code like:
>> for (i = 20; i > 0; i--) {
>>   msleep(50);
>>
>> If there is no-LOCK then dvbv5-scan spent a lot of time (doing 40x calls).
>> This patch introduce timeout which 4 sec * multiply. So we do not wait more
>> than 4 sec (or so) if no-LOCK.
>>
>> Signed-off-by: Abylay Ospan <aospan@netup.ru>
>> ---
>>  utils/dvb/dvbv5-scan.c | 15 +++++++++++++++
>>  1 file changed, 15 insertions(+)
>>
>> diff --git a/utils/dvb/dvbv5-scan.c b/utils/dvb/dvbv5-scan.c
>> index 689bc0b..1fc33d7 100644
>> --- a/utils/dvb/dvbv5-scan.c
>> +++ b/utils/dvb/dvbv5-scan.c
>> @@ -182,12 +182,23 @@ static int print_frontend_stats(struct arguments *args,
>>       return 0;
>>  }
>>
>> +/* return timestamp in msec */
>> +uint64_t get_timestamp()
>> +{
>> +     struct timeval now;
>> +     gettimeofday(&now, 0);
>> +     return now.tv_sec * 1000 + now.tv_usec/1000;
>
> This is not good, as gettimeofday() is not monotonic, and may be affected
> by clock adjustments.
>
> IMHO, the best would be to adjust the do_timeout() to handle
> args->timeout_multiply.
>
> Regards,
> Mauro
>
>> +}
>> +
>>  static int check_frontend(void *__args,
>>                         struct dvb_v5_fe_parms *parms)
>>  {
>>       struct arguments *args = __args;
>>       int rc, i;
>>       fe_status_t status;
>> +     uint64_t start = get_timestamp();
>> +     /* msec timeout by default 4 sec * multiply */
>> +     uint64_t timeout = args->timeout_multiply * 4 * 1000;
>>
>>       args->n_status_lines = 0;
>>       for (i = 0; i < args->timeout_multiply * 40; i++) {
>> @@ -203,6 +214,10 @@ static int check_frontend(void *__args,
>>               print_frontend_stats(args, parms);
>>               if (status & FE_HAS_LOCK)
>>                       break;
>> +
>> +             if ((get_timestamp() - start) > timeout)
>> +                     break;
>> +
>>               usleep(100000);
>
> It would also make sense to remove the usleep here and
> use something else that would be checking timeout_flag,
> like:
>
>         for (i = 1; i < 100; i++) {
>                 if (timeout_flag)
>                         break;
>                 usleep(1000);
>         }
>
>
> --
> Thanks,
> Mauro



-- 
Abylay Ospan,
NetUP Inc.
http://www.netup.tv

Re: [PATCH] [dvbv5-scan] wait no more than timeout when scanning

[Abylay Ospan]

Hi Mauro,

I have sent two patches to ML. One is for dvbv5-scan (v3 of this
patch) and second for lgdt3306a driver. Now I have achieved 4 minutes
for full scan (file us-ATSC-center-frequencies-8VSB with 68
frequencies inside). This is much better than 2 hours before :)
But need to test this patches if possible. Who works with lgdt3306a -
please test. Hope nothing is broken.

Thanks !

2016-07-22 15:18 GMT-04:00 Mauro Carvalho Chehab <mchehab@osg.samsung.com>:
> Hi Abylay,
>
> Em Fri, 22 Jul 2016 13:54:37 -0400
> Abylay Ospan <aospan@netup.ru> escreveu:
>
>> some frontends (mentioned on lgdt3306a) wait timeout inside code like:
>> for (i = 20; i > 0; i--) {
>>   msleep(50);
>>
>> If there is no-LOCK then dvbv5-scan spent a lot of time (doing 40x calls).
>> This patch introduce timeout which 4 sec * multiply. So we do not wait more
>> than 4 sec (or so) if no-LOCK.
>>
>> Signed-off-by: Abylay Ospan <aospan@netup.ru>
>> ---
>>  utils/dvb/dvbv5-scan.c | 15 +++++++++++++++
>>  1 file changed, 15 insertions(+)
>>
>> diff --git a/utils/dvb/dvbv5-scan.c b/utils/dvb/dvbv5-scan.c
>> index 689bc0b..1fc33d7 100644
>> --- a/utils/dvb/dvbv5-scan.c
>> +++ b/utils/dvb/dvbv5-scan.c
>> @@ -182,12 +182,23 @@ static int print_frontend_stats(struct arguments *args,
>>       return 0;
>>  }
>>
>> +/* return timestamp in msec */
>> +uint64_t get_timestamp()
>> +{
>> +     struct timeval now;
>> +     gettimeofday(&now, 0);
>> +     return now.tv_sec * 1000 + now.tv_usec/1000;
>
> This is not good, as gettimeofday() is not monotonic, and may be affected
> by clock adjustments.
>
> IMHO, the best would be to adjust the do_timeout() to handle
> args->timeout_multiply.
>
> Regards,
> Mauro
>
>> +}
>> +
>>  static int check_frontend(void *__args,
>>                         struct dvb_v5_fe_parms *parms)
>>  {
>>       struct arguments *args = __args;
>>       int rc, i;
>>       fe_status_t status;
>> +     uint64_t start = get_timestamp();
>> +     /* msec timeout by default 4 sec * multiply */
>> +     uint64_t timeout = args->timeout_multiply * 4 * 1000;
>>
>>       args->n_status_lines = 0;
>>       for (i = 0; i < args->timeout_multiply * 40; i++) {
>> @@ -203,6 +214,10 @@ static int check_frontend(void *__args,
>>               print_frontend_stats(args, parms);
>>               if (status & FE_HAS_LOCK)
>>                       break;
>> +
>> +             if ((get_timestamp() - start) > timeout)
>> +                     break;
>> +
>>               usleep(100000);
>
> It would also make sense to remove the usleep here and
> use something else that would be checking timeout_flag,
> like:
>
>         for (i = 1; i < 100; i++) {
>                 if (timeout_flag)
>                         break;
>                 usleep(1000);
>         }
>
>
> --
> Thanks,
> Mauro



-- 
Abylay Ospan,
NetUP Inc.
http://www.netup.tv

[PATCH] [dvbv5-scan] wait no more than timeout when scanning

[Abylay Ospan]

some frontends (mentioned on lgdt3306a) wait timeout inside code like:
for (i = 20; i > 0; i--) {
  msleep(50);

If there is no-LOCK then dvbv5-scan spent a lot of time (doing 40x calls).
This patch introduce timeout which 4 sec * multiply. So we do not wait more
than 4 sec (or so) if no-LOCK.
CLOCK_MONOTONIC is used so we don't care about timestamps "rollup"

Signed-off-by: Abylay Ospan <aospan@netup.ru>
---
 utils/dvb/dvbv5-scan.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/utils/dvb/dvbv5-scan.c b/utils/dvb/dvbv5-scan.c
index 689bc0b..f6bb3fc 100644
--- a/utils/dvb/dvbv5-scan.c
+++ b/utils/dvb/dvbv5-scan.c
@@ -182,12 +182,23 @@ static int print_frontend_stats(struct arguments *args,
 	return 0;
 }
 
+/* return timestamp in msec */
+uint64_t get_timestamp()
+{
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+	return now.tv_sec * 1000 + now.tv_nsec/1000000;
+}
+
 static int check_frontend(void *__args,
 			  struct dvb_v5_fe_parms *parms)
 {
 	struct arguments *args = __args;
 	int rc, i;
 	fe_status_t status;
+	uint64_t start = get_timestamp();
+	/* msec timeout by default 4 sec * multiply */ 
+	uint64_t timeout = args->timeout_multiply * 4 * 1000;
 
 	args->n_status_lines = 0;
 	for (i = 0; i < args->timeout_multiply * 40; i++) {
@@ -203,6 +214,10 @@ static int check_frontend(void *__args,
 		print_frontend_stats(args, parms);
 		if (status & FE_HAS_LOCK)
 			break;
+
+		if ((get_timestamp() - start) > timeout)
+			break;
+
 		usleep(100000);
 	};
 
-- 
2.7.4