[LTP] [PATCH v4] fzsync: limit sampling time

[Richard Palethorpe]

Hell Jan,

Jan Stancek <jstancek@redhat.com> writes:

> ----- Original Message -----
>> Fixes: #429
>> 
>> Sampling can take considerably longer time on single CPU
>> and very slow systems. This patch limits sampling time to
>> 1/2 of fuzzing runtime. If we don't have enough samples by
>> that time, stop sampling and use stats we gathered so far.
>
> @Richard: Are you OK with v4 (with %% typo fixed)?

Yes, thanks.

>
>> 
>> Signed-off-by: Jan Stancek <jstancek@redhat.com>
>> ---
>>  include/tst_fuzzy_sync.h | 21 ++++++++++++++-------
>>  1 file changed, 14 insertions(+), 7 deletions(-)
>> 
>> Changes in v4:
>>  - drop comment
>>  - tweak info message when timeout is reached
>> 
>> diff --git a/include/tst_fuzzy_sync.h b/include/tst_fuzzy_sync.h
>> index 03f69b78bc82..0e534bb041f8 100644
>> --- a/include/tst_fuzzy_sync.h
>> +++ b/include/tst_fuzzy_sync.h
>> @@ -70,6 +70,9 @@
>>  #ifndef TST_FUZZY_SYNC_H__
>>  #define TST_FUZZY_SYNC_H__
>>  
>> +/* how much of exec time is sampling allowed to take */
>> +#define SAMPLING_SLICE 0.5f
>> +
>>  /** Some statistics for a variable */
>>  struct tst_fzsync_stat {
>>  	float avg;
>> @@ -582,17 +585,21 @@ static inline void tst_fzsync_wait_b(struct
>> tst_fzsync_pair *pair)
>>  static inline int tst_fzsync_run_a(struct tst_fzsync_pair *pair)
>>  {
>>  	int exit = 0;
>> +	float rem_p = 1 - tst_timeout_remaining() / pair->exec_time_start;
>> +
>> +	if ((pair->exec_time_p * SAMPLING_SLICE < rem_p)
>> +		&& (pair->sampling > 0)) {
>> +		tst_res(TINFO, "Stopped sampling at %d (out of %d) samples, "
>> +			"sampling time reached 50% of the total time limit",
>> +			pair->exec_loop, pair->min_samples);
>> +		pair->sampling = 0;
>> +		tst_fzsync_pair_info(pair);
>> +	}
>>  
>> -	if (pair->exec_time_p
>> -	    < 1 - tst_timeout_remaining() / pair->exec_time_start) {
>> +	if (pair->exec_time_p < rem_p) {
>>  		tst_res(TINFO,
>>  			"Exceeded execution time, requesting exit");
>>  		exit = 1;
>> -
>> -		if (pair->sampling > 0) {
>> -			tst_res(TWARN,
>> -				"Still sampling, consider increasing LTP_TIMEOUT_MUL");
>> -		}
>>  	}
>>  
>>  	if (++pair->exec_loop > pair->exec_loops) {
>> --
>> 1.8.3.1
>> 
>> 
>> --
>> Mailing list info: https://lists.linux.it/listinfo/ltp
>> 


-- 
Thank you,
Richard.