Re: [LTP] [PATCH] [syscalls] getrusage04: new testcase

[Caspar Z. <ca...@ca...>]

On 07/28/2011 12:10 AM, Cyril Hrubis wrote:
> Hi!
>> +#define RUSAGE_THREAD 1
> 
> Shouldn't this be set in system headers?
> 
> And even if not, it probably would be on newer systems so better way
> should be:
> 
> #ifndef RUSAGE_THREAD
> #define RUSAGE_THREAD 1
> #endif

corrected.

> 
>> +static void busyloop(int wait);
>> +static void setup(void);
>> +static void cleanup(void);
>> +
>> +int main(int argc, char *argv[])
>> +{
>> +	struct rusage usage;
>> +	unsigned long ulast, udelta, slast, sdelta;
>> +	int i, lc;
>> +	char *msg;
>> +
>> +	msg = parse_opts(argc, argv, NULL, NULL);
>> +	if (msg != NULL)
>> +		tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);
>> +
>> +	setup();
>> +
>> +	for (lc = 0; TEST_LOOPING(lc); lc++) {
>> +		Tst_count = 0; i = 0;
>> +		ulast = 0, slast = 0;
>> +		SAFE_GETRUSAGE(cleanup, RUSAGE_THREAD, &usage);
>> +		tst_resm(TINFO, "utime:%12luus; stime:%12luus",
>> +			usage.ru_utime.tv_usec, usage.ru_stime.tv_usec);
>> +		while (i < RECORD_MAX) {
>> +			SAFE_GETRUSAGE(cleanup, RUSAGE_THREAD, &usage);
>> +			udelta = usage.ru_utime.tv_usec - ulast;
>> +			sdelta = usage.ru_stime.tv_usec - slast;
>> +			if (udelta > 0 || sdelta > 0) {
>> +				i++;
>> +				tst_resm(TINFO, "utime:%12luus; stime:%12luus",
>> +					    usage.ru_utime.tv_usec,
>> +					    usage.ru_stime.tv_usec);
>> +				if (udelta > 1000+BIAS_MAX)
>> +					tst_brkm(TFAIL, cleanup,
>> +						    "utime increased > 1000us:"
>> +						    " delta = %luus", udelta);
>> +				if (sdelta > 1000+BIAS_MAX)
>> +					tst_brkm(TFAIL, cleanup,
>> +						    "stime increased > 1000us:"
>> +						    " delta = %luus", sdelta);
>> +			}
>> +			ulast = usage.ru_utime.tv_usec;
>> +			slast = usage.ru_stime.tv_usec;
> 
> Hmm, you are actually looping the test for RECORD_MAX and then the whole
> test in test loop. Is there really need for that redundancy?  Shouldn't
> be running the test with -i 20 sufficient?

-i 20 is not enough, the while-loop goes more than 20 times since there
is a condition:


+			if (udelta > 0 || sdelta > 0) {
+				i++;

only when both deltas > 0, the counter increases by 1.

> 
>> +			busyloop(100000);
>> +		}
>> +	}
>> +	cleanup();
>> +	tst_exit();
>> +}
>> +
>> +static void busyloop(int wait)
>> +{
>> +	int i, j = 0;
>> +
>> +	for (i = 0; i < wait; i++)
>> +		j = j * 3 + 11;
> 
> The j = j * 3 + 11 line would likely by removed by compiler
> optimalization.
> 
> Also if you wan't to create bussy loop that loops for some microseconds
> you can use posix timers for that. Something like:

The loop is mainly for consuming some resources to increase CPU time, so
I removed j = j * 3 + 11 line, and use a while loop instead:

while (wait--)
    ;

> 
> 
> void sighandler(int sig)
> {
> 	signal_flag = 0;
> }
> 
> void bussy_loop(void)
> {
> 	while (signal_flag);
> }
> 
> ...
> 
> 
> timer_create()
> 
> ...
> 
> signal_flag = 1;
> timer_settime();
> bussy_loop();
>