aboutsummaryrefslogtreecommitdiff
path: root/tests/jittertest/JitterTest.c
blob: 4627fb07af1400202aa326e50b956ece79c6d21a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
/***********************************************************************
 *
 *  Copyright:          Daniel Measurement and Control, Inc.
 *                           9753 Pine Lake Drive
 *                             Houston, TX 77055
 *
 *  Created by: Vipin Malik and Gail Murray
 *  Released under GPL by permission of Daniel Industries.
 *
 * This software is licensed under the GPL version 2. Plese see the file
 * COPYING for details on the license.
 *
 * NO WARRANTY: Absolutely no claims of warranty or fitness of purpose
 *              are made in this software. Please use at your own risk.
 *
 *  Filename:     JitterTest.c
 *
 *  Description:  Program to be used to measure wake jitter.
 *                See README file for more info.
 *
 *
 *  Revision History:
 *  $Id: JitterTest.c,v 1.13 2005/11/07 11:15:20 gleixner Exp $
 *  $Log: JitterTest.c,v $
 *  Revision 1.13  2005/11/07 11:15:20  gleixner
 *  [MTD / JFFS2] Clean up trailing white spaces
 *
 *  Revision 1.12  2001/08/10 19:23:11  vipin
 *  Ready to be released under GPL! Added proper headers etc.
 *
 *  Revision 1.11  2001/07/09 15:35:50  vipin
 *  Couple of new features:1. The program runs by default as a "regular"
 *  (SCHED_OTHER) task by default, unless the -p n cmd line parameter is
 *  specified. It then runs as SCHED_RR at that priority.
 *  2. Added ability to send SIGSTOP/SIGCONT to a specified PID. This
 *  would presumably be the PID of the JFFS2 GC task. SIGSTOP is sent
 *  before writing to the fs, and a SIGCONT after the write is done.
 *  3. The "pad" data now written to the file on the "fs under test" is
 *  random, not sequential as previously.
 *
 *  Revision 1.10  2001/06/27 19:14:24  vipin
 *  Now console file to log at can be specified from cmd line. This can enable
 *  you to run two instances of the program- one logging to the /dev/console
 *  and another to a regular file (if you want the data) or /dev/null if you don't.
 *
 *  Revision 1.9  2001/06/25 20:21:31  vipin
 *  This is the latest version, NOT the one last checked in!
 *
 *  Revision 1.7  2001/06/18 22:36:19  vipin
 *  Fix minor typo that excluded '\n' from msg on console.
 *
 *  Revision 1.6  2001/06/18 21:17:50  vipin
 *  Added option to specify the amount of data written to outfile each period.
 *  The regular info is written, but is then padded to the requested size.
 *  This will enable testing of different sized writes to JFFS fs.
 *
 *  Revision 1.5  2001/06/08 19:36:23  vipin
 *  All write() are now checked for return err code.
 *
 *  Revision 1.4  2001/06/06 23:10:31  vipin
 *  Added README file.
 *  In JitterTest.c: Changed operation of periodic timer to one shot. The timer is now
 *  reset when the task wakes. This way every "jitter" is from the last time and
 *  jitters from previous times are not accumulated and screw aroud with our display.
 *
 *  All jitter is now +ve. (as it should be). Also added a "read file" functionality
 *  to test for jitter in task if we have to read from JFFS fs.
 *  The program now also prints data to console- where it can be logged, interspersed with
 *  other "interesting" printk's from the kernel and drivers (flash sector erases etc.)
 *
 *  Revision 1.3  2001/03/01 19:20:39  gmurray
 *  Add priority scheduling. Shortened name of default output file.
 *  Changed default interrupt period. Output delta time and jitter
 *  instead of time of day.
 *
 *  Revision 1.2  2001/02/28 16:20:19  vipin
 *  Added version control Id and log fields.
 *
 ***********************************************************************/
/*************************** Included Files ***************************/
#include <stdio.h>      /* fopen, printf, fprintf, fclose */
#include <string.h>     /* strcpy, strcmp */
#include <stdlib.h>     /* exit, atol, atoi */
#include <sys/time.h>   /* setitimer, settimeofday, gettimeofday */
#include <time.h>	/* time */
#include <signal.h>     /* signal */
#include <sched.h>      /* sched_setscheduler, sched_get_priority_min,*/
/*   sched_get_priority_max */
#include <unistd.h>     /* gettimeofday, sleep */
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>

#define PROGRAM_NAME "JitterTest"
#include "common.h"

/**************************** Enumerations ****************************/
enum timerActions
    {
        ONESHOT,
        AUTORESETTING
    };



/****************************** Constants *****************************/
/* Exit error codes */
#define EXIT_FILE_OPEN_ERR        (1)     /* error opening output file*/
#define EXIT_REG_SIGALRM_ERR      (2)     /* error registering SIGALRM*/
#define EXIT_REG_SIGINT_ERR       (3)     /* error registering SIGINT */
#define EXIT_INV_INT_PERIOD       (4)     /* error invalid int. period*/
#define EXIT_MIN_PRIORITY_ERR     (5)     /* error, minimum priority  */
#define EXIT_MAX_PRIORITY_ERR     (6)     /* error, maximum priority  */
#define EXIT_INV_SCHED_PRIORITY   (7)     /* error, invalid priority  */
#define EXIT_SET_SCHEDULER_ERR    (8)     /* error, set scheduler     */
#define EXIT_PREV_TIME_OF_DAY_ERR (9)     /* error, init. prev.       */
/*   time of day            */

#define MAX_FILE_NAME_LEN         (32)    /* maximum file name length */

#define STRINGS_EQUAL             ((int) 0) /* strcmp value if equal  */

#define MIN_INT_PERIOD_MILLISEC   (   5L) /* minimum interrupt period */
#define MAX_INT_PERIOD_MILLISEC   (5000L) /* maximum interrupt period */
#define DEF_INT_PERIOD_MILLISEC   (  10L) /* default interrupt period */

#define READ_FILE_MESSAGE "This is a junk file. Must contain at least 1 byte though!\n"

/* The user can specify that the program pad out the write file to
   a given number of bytes. But a minimum number needs to be written. This
   will contain the jitter info.
*/
#define MIN_WRITE_BYTES     30
#define DEFAULT_WRITE_BYTES 30
#define MAX_WRITE_BYTES 4096

/* used for gen a printable ascii random # between spc and '~' */
#define MIN_ASCII 32     /* <SPACE> can be char*/
#define MAX_ASCII 126.0 /* needs to be float. See man rand()  */

/*----------------------------------------------------------------------
 * It appears that the preprocessor can't handle multi-line #if
 * statements. Thus, the check on the default is divided into two
 * #if statements.
 *---------------------------------------------------------------------*/
#if (DEF_INT_PERIOD_MILLISEC < MIN_INT_PERIOD_MILLISEC)
#error *** Invalid default interrupt period. ***
#endif

#if (DEF_INT_PERIOD_MILLISEC > MAX_INT_PERIOD_MILLISEC)
#error *** Invalid default interrupt period. ***
#endif


#define TRUE                      1  /* Boolean true value       */
#define FALSE                     0

/* Time conversion constants. */
#define MILLISEC_PER_SEC          (1000L) /* milliseconds per second  */
#define MICROSEC_PER_MILLISEC     (1000L) /* microsecs per millisec   */
#define MICROSEC_PER_SEC          (1000000L) /* microsecs per second  */

#define PRIORITY_POLICY           ((int) SCHED_RR) /* If specified iwth "-p" */



/************************** Module Variables **************************/
static char OutFileName[MAX_FILE_NAME_LEN+1];  /* output file name            */
static char LogFile[MAX_FILE_NAME_LEN+1] = "/dev/console"; /* default */
static char ReadFile[MAX_FILE_NAME_LEN+1]; /* This file is read. Should
                                              contain at least 1 byte */

static int WriteBytes = DEFAULT_WRITE_BYTES; /* pad out file to these many bytes. */
static int Fd1;                        /* fd where the above buffer if o/p */
static int Cfd;                        /* fd to console (or file specified) */
static int Fd2;                        /* fd for the ReadFile         */
static int DoRead = FALSE;             /* should we attempt to ReadFile?*/
static long InterruptPeriodMilliSec;   /* interrupt period, millisec  */
static int MinPriority;                /* minimum scheduler priority  */
static int MaxPriority;                /* maximum scheduler priority  */
static int RequestedPriority;          /* requested priority          */
static struct itimerval ITimer;        /* interrupt timer structure   */
static struct timeval PrevTimeVal;     /* previous time structure     */
static struct timeval CurrTimeVal;     /* current time structure      */
static long LastMaxDiff = 0; /* keeps track of worst jitter encountered */

static int GrabKProfile = FALSE; /* To help determine system bottle necks
                                    this parameter can be set. This causes
                                    the /proc/profile file to be read and
                                    stored in unique filenames in current
                                    dir, and indication to be o/p on the
                                    /dev/console also.
                                 */
static long ProfileTriggerMSecs = 15000l; /* Jitter time in seconds that triggers
                                       a snapshot of the profile to be taken

                                    */
static int SignalGCTask = FALSE; /* should be signal SIGSTOP/SIGCONT to gc task?*/
static int GCTaskPID;

static int RunAsRTTask = FALSE; /* default action unless priority is
				   specified on cmd line */


/********************* Local Function Prototypes **********************/
void HandleCmdLineArgs(int argc, char *argv[]);
void SetFileName(char * pFileName);
void SetInterruptPeriod(char * pASCIIInterruptPeriodMilliSec);
void SetSchedulerPriority(char * pASCIISchedulerPriority);

void PrintVersionInfo(void);
void PrintHelpInfo(void);

int Write(int fd, void *buf, size_t bytes, int lineNo);

void InitITimer(struct itimerval * pITimer, int action);

/* For catching timer interrupts (SIGALRM). */
void AlarmHandler(int sigNum);

/* For catching Ctrl+C SIGINT. */
void SignalHandler(int sigNum);



/***********************************************************************
 *  main function
 *  return: exit code
 ***********************************************************************/
int main(
    int argc,
    char *argv[])
{
    struct sched_param schedParam;

    int mypri;
    char tmpBuf[200];


    strcpy(OutFileName,"jitter.dat");
    InterruptPeriodMilliSec = MIN_INT_PERIOD_MILLISEC;

    /* Get the minimum and maximum priorities. */
    MinPriority = sched_get_priority_min(PRIORITY_POLICY);
    MaxPriority = sched_get_priority_max(PRIORITY_POLICY);
    if (MinPriority == -1) {
        printf("\n*** Unable to get minimum priority. ***\n");
        exit(EXIT_MIN_PRIORITY_ERR);
    }
    if (MaxPriority == -1) {
        printf("\n*** Unable to get maximum priority. ***\n");
        exit(EXIT_MAX_PRIORITY_ERR);
    }

    /* Set requested priority to minimum value as default. */
    RequestedPriority = MinPriority;

    HandleCmdLineArgs(argc, argv);

    if(mlockall(MCL_CURRENT|MCL_FUTURE) < 0){
        printf("Could not lock task into memory. Bye\n");
        perror("Error");
    }

    if(RunAsRTTask){

        /* Set the priority. */
        schedParam.sched_priority = RequestedPriority;
	if (sched_setscheduler(
			       0,
			       PRIORITY_POLICY,
			       &schedParam) != (int) 0) {
	  printf("Exiting: Unsuccessful sched_setscheduler.\n");
	  close(Fd1);
	  exit(EXIT_SET_SCHEDULER_ERR);
	}


	/* Double check as I have some doubts that it's really
	   running at realtime priority! */
	if((mypri = sched_getscheduler(0)) != RequestedPriority)
	  {
	    printf("Not running with request priority %i. running with priority %i instead!\n",
		   RequestedPriority, mypri);
	  }else
	    {
	      printf("Running with %i priority. Good!\n", mypri);
	    }

    }

    /*------------------------- Initializations --------------------------*/
    if((Fd1 = open(OutFileName, O_RDWR|O_CREAT|O_SYNC, S_IRWXU)) <= 0)
    {
        perror("Cannot open outfile for write:");
        exit(1);
    }

    /* If a request is made to read from a specified file, then create that
       file and fill with junk data so that there is something there to read.
    */
    if(DoRead)
    {

        if((Fd2 = open(ReadFile, O_RDWR|O_CREAT|O_SYNC|O_TRUNC, S_IRWXU)) <= 0)
        {
            perror("cannot open read file:");
            exit(1);
        }else
        {

            /* Don't really care how much we write here */
            if(write(Fd2, READ_FILE_MESSAGE, strlen(READ_FILE_MESSAGE)) < 0)
            {
                perror("Problems writing to readfile:");
                exit(1);
            }
            lseek(Fd2, 0, SEEK_SET); /* position back to byte #0 */
        }
    }



    /* Also log output to console. This way we can capture it
       on a serial console to a log file.
    */
    if((Cfd   = open(LogFile, O_WRONLY|O_SYNC)) <= 0)
    {
        perror("cannot open o/p logfile:");
        exit(1);
    }


    /* Set-up handler for periodic interrupt. */
    if (signal(SIGALRM, &AlarmHandler) == SIG_ERR) {
        printf("Couldn't register signal handler for SIGALRM.\n");
        sprintf(tmpBuf,
                "Couldn't register signal handler for SIGALRM.\n");
        Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);

        close(Fd1);
        exit(EXIT_REG_SIGALRM_ERR);
    }

    /* Set-up handler for Ctrl+C to exit the program. */
    if (signal(SIGINT, &SignalHandler) == SIG_ERR) {
        printf("Couldn't register signal handler for SIGINT.\n");
        sprintf(tmpBuf,
                "Couldn't register signal handler for SIGINT.\n");
        Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);

        close(Fd1);
        exit(EXIT_REG_SIGINT_ERR);
    }

    printf("Press Ctrl+C to exit the program.\n");
    printf("Output File:        %s\n", OutFileName);
    printf("Scheduler priority: %d\n", RequestedPriority);
    sprintf(tmpBuf, "\nScheduler priority: %d\n",
            RequestedPriority);
    Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);

    Write(Cfd, tmpBuf, strlen(tmpBuf), __LINE__);

    printf("Interrupt period:   %ld milliseconds\n",
           InterruptPeriodMilliSec);
    sprintf(tmpBuf, "Interrupt period:   %ld milliseconds\n",
            InterruptPeriodMilliSec);

    Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);

    Write(Cfd, tmpBuf, strlen(tmpBuf), __LINE__);


    fflush(0);



    /* Initialize the periodic timer. */
    InitITimer(&ITimer, ONESHOT);

    /* Initialize "previous" time. */
    if (gettimeofday(&PrevTimeVal, NULL) != (int) 0) {
        printf("Exiting - ");
        printf("Unable to initialize previous time of day.\n");
        sprintf(tmpBuf, "Exiting - ");
        Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);

        sprintf(tmpBuf,
                "Unable to initialize previous time of day.\n");

        Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);

    }

    /* Start the periodic timer. */
    setitimer(ITIMER_REAL, &ITimer, NULL);


    while(TRUE) {    /* Intentional infinite loop. */
        /* Sleep for one second. */
        sleep((unsigned int) 1);
    }

    /* Just in case. File should be closed in SignalHandler. */
    close(Fd1);
    close(Cfd);

    return 0;
}




/***********************************************************************
 *                                SignalHandler
 *  This is a handler for the SIGINT signal. It is assumed that the
 *  SIGINT is due to the user pressing Ctrl+C to halt the program.
 *  output: N/A
 ***********************************************************************/
void SignalHandler(
    int sigNum)
{

    char tmpBuf[200];

    /* Note sigNum not used. */
    (void)sigNum;

    printf("Ctrl+C detected. Worst Jitter time was:%fms.\nJitterTest exiting.\n",
           (float)LastMaxDiff/1000.0);

    sprintf(tmpBuf,
            "\nCtrl+C detected. Worst Jitter time was:%fms\nJitterTest exiting.\n",
            (float)LastMaxDiff/1000.0);
    Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);

    Write(Cfd, tmpBuf, strlen(tmpBuf), __LINE__);

    close(Fd1);
    close(Cfd);
    exit(0);
}





/*
  A snapshot of the /proc/profile needs to be taken.
  This is stored as a new file every time, and the
  stats reset by doing a (any) write to the /proc/profile
  file.
 */
static void doGrabKProfile(int jitterusec, char *fileName)
{
    int fdSnapshot;
    int fdProfile;
    int readBytes;
    char readBuf[4096];

    (void)jitterusec;

    if((fdSnapshot = open(fileName, O_WRONLY | O_CREAT, S_IRWXU)) <= 0)
    {
        fprintf(stderr, "Could not open file %s.\n", fileName);
        perror("Error:");
        return;
    }

    if((fdProfile = open("/proc/profile", O_RDWR)) <= 0)
    {
        fprintf(stderr, "Could not open file /proc/profile. Make sure you booted with profile=2\n");
        close(fdSnapshot);
        return;
    }

    while((readBytes = read(fdProfile, readBuf, sizeof(readBuf))) > 0)
    {
	int writeBytes = write(fdSnapshot, readBuf, readBytes);
	if (writeBytes != readBytes) {
		perror("write error");
		break;
	}
    }

    close(fdSnapshot);

    if(write(fdProfile, readBuf, 1) != 1)
    {
        perror("Could Not clear profile by writing to /proc/profile:");
    }

    close(fdProfile);



}/* end doGrabKProfile()*/


/*
  Call this routine to clear the kernel profiling buffer /proc/profile
*/
static void clearProfileBuf(void){


  int fdProfile;
  char readBuf[10];


  if((fdProfile = open("/proc/profile", O_RDWR)) <= 0)
    {
      fprintf(stderr, "Could not open file /proc/profile. Make sure you booted with profile=2\n");
      return;
    }


  if(write(fdProfile, readBuf, 1) != 1)
    {
      perror("Could Not clear profile by writing to /proc/profile:");
    }

  close(fdProfile);


}/* end clearProfileBuf() */





/***********************************************************************
 *                                AlarmHandler
 *  This is a handler for the SIGALRM signal (due to the periodic
 *  timer interrupt). It prints the time (seconds) to
 *  the output file.
 *  output: N/A
 ***********************************************************************/
void AlarmHandler(
    int sigNum)                     /* signal number (not used)         */
{

    long timeDiffusec;  /* diff time in micro seconds */
    long intervalusec;


    char tmpBuf[MAX_WRITE_BYTES];
    int cntr;
    char padChar;

    static int profileFileNo = 0;
    char profileFileName[150];

    static int seedStarter = 0; /* carries over rand info to next time
				   where time() will be the same as this time
				   if invoked < 1sec apart.
				*/

    (void)sigNum;

    if (gettimeofday(&CurrTimeVal, NULL) == (int) 0) {

        /*----------------------------------------------------------------
         * Compute the elapsed time between the current and previous
         * time of day values and store the result.
         *
         * Print the elapsed time to the output file.
         *---------------------------------------------------------------*/

        timeDiffusec = (long)(((((long long)CurrTimeVal.tv_sec) * 1000000L) + CurrTimeVal.tv_usec) -
                        (((long long)PrevTimeVal.tv_sec * 1000000L) + PrevTimeVal.tv_usec));

        sprintf(tmpBuf," %f ms  ", (float)timeDiffusec/1000.0);

        intervalusec = InterruptPeriodMilliSec * 1000L;

        timeDiffusec = timeDiffusec - intervalusec;

        sprintf(&tmpBuf[strlen(tmpBuf)]," %f ms", (float)timeDiffusec/1000.0);


	/* should we send a SIGSTOP/SIGCONT to the specified PID? */
	if(SignalGCTask){

	  if(kill(GCTaskPID, SIGSTOP) < 0){

	    perror("error:");
	  }
	}


        /* Store some historical #'s */
        if(abs(timeDiffusec) > LastMaxDiff)
	{
            LastMaxDiff = abs(timeDiffusec);
            sprintf(&tmpBuf[strlen(tmpBuf)],"!");

	    if((GrabKProfile == TRUE) && (ProfileTriggerMSecs < (abs(timeDiffusec)/1000)))
	      {
		  sprintf(profileFileName, "JitterTest.profilesnap-%i", profileFileNo);

		  /* go and grab the kernel performance profile. */
		  doGrabKProfile(timeDiffusec, profileFileName);
		  profileFileNo++; /* unique name next time */

		  /* Say so on the console so that a marker gets put in the console log */
		  sprintf(&tmpBuf[strlen(tmpBuf)],"<Profile saved in file:%s>",
			  profileFileName);

	      }

        }




        sprintf(&tmpBuf[strlen(tmpBuf)],"\n"); /* CR for the data going out of the console */

        Write(Cfd, tmpBuf, strlen(tmpBuf), __LINE__);


        /* The "-1" below takes out the '\n' at the end that we appended for the msg printed on
         the console.*/
        sprintf(&tmpBuf[strlen(tmpBuf)-1]," PadBytes:");

        /* Now pad the output file if requested by user. */
        if(WriteBytes > MIN_WRITE_BYTES)
        {

	    /* start from a new place every time */
	    srand(time(NULL) + seedStarter);

            /* already written MIN_WRITE_BYTES by now */
            for(cntr = strlen(tmpBuf); cntr < WriteBytes - 1 ; cntr++) /* "-1" adj for '\n' at end */
            {
	        /* don't accept any # < 'SPACE' */
	        padChar = (char)(MIN_ASCII+(int)((MAX_ASCII-(float)MIN_ASCII)*rand()/(RAND_MAX+1.0)));


                /*
                padChar = (cntr % (126-33)) + 33;
		*/

                tmpBuf[cntr] = padChar;
            }

	    seedStarter = tmpBuf[cntr-1]; /* save for next time */

            tmpBuf[cntr] = '\n'; /* CR for the data going into the outfile. */
            tmpBuf[cntr+1] = '\0'; /* NULL terminate the string */
        }

        /* write out the entire line to the output file. */
        Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);


        /* Read a byte from the specified file */
        if(DoRead)
        {

	    cntr = read(Fd2, tmpBuf, 1);
	    if (cntr < 0)
		perror("read error");
            lseek(Fd2, 0, SEEK_SET); /* back to start */
        }


        /* Start the periodic timer again. */
        setitimer(ITIMER_REAL, &ITimer, NULL);


        /* Update previous time with current time. */
        PrevTimeVal.tv_sec  = CurrTimeVal.tv_sec;
        PrevTimeVal.tv_usec = CurrTimeVal.tv_usec;
    }

    else {
        sprintf(tmpBuf, "gettimeofday error \n");
        Write(Fd1, tmpBuf, strlen(tmpBuf), __LINE__);

        printf("gettimeofday error \n");
    }

    /* now clear the profiling buffer */
    if(GrabKProfile == TRUE){

      clearProfileBuf();
    }

    /* should we send a SIGSTOP/SIGCONT to the specified PID? */
    if(SignalGCTask){

      if(kill(GCTaskPID, SIGCONT) < 0){

	perror("error:");
      }
    }


    return;
}



/***********************************************************************
 *                                 InitITimer
 *  This function initializes the 'struct itimerval' structure whose
 *  address is passed to interrupt every InterruptPeriodMilliSec.
 *  output: N/A
 ***********************************************************************/
void InitITimer(
    struct itimerval * pITimer,      /* pointer to interrupt timer struct*/
    int action)                      /* ONESHOT or autosetting? */
{
    long seconds;                   /* seconds portion of int. period   */
    long microSeconds;              /* microsec. portion of int. period */

    /*--------------------------------------------------------------------
     * Divide the desired interrupt period into its seconds and
     * microseconds components.
     *-------------------------------------------------------------------*/
    if (InterruptPeriodMilliSec < MILLISEC_PER_SEC)  {
        seconds = 0L;
        microSeconds = InterruptPeriodMilliSec * MICROSEC_PER_MILLISEC;
    }
    else {
        seconds = InterruptPeriodMilliSec / MILLISEC_PER_SEC;
        microSeconds =
            (InterruptPeriodMilliSec - (seconds * MILLISEC_PER_SEC)) *
            MICROSEC_PER_MILLISEC;
    }

    /* Initialize the interrupt period structure. */
    pITimer->it_value.tv_sec     = seconds;
    pITimer->it_value.tv_usec    = microSeconds;

    if(action == ONESHOT)
    {
        /* This will (should) prevent the timer from restarting itself */
        pITimer->it_interval.tv_sec  = 0;
        pITimer->it_interval.tv_usec = 0;
    }else
    {
        pITimer->it_interval.tv_sec  = seconds;
        pITimer->it_interval.tv_usec = microSeconds;

    }

    return;
}


/***********************************************************************
 *                             HandleCmdLineArgs
 *  This function handles the command line arguments.
 *  output: stack size
 ***********************************************************************/
void HandleCmdLineArgs(
    int argc,                       /* number of command-line arguments */
    char *argv[])                   /* ptrs to command-line arguments   */
{
    int argNum;                     /* argument number                  */

    if (argc > (int) 1) {

        for (argNum = (int) 1; argNum < argc; argNum++) {

            /* The command line contains an argument. */

            if ((strcmp(argv[argNum],"--version") == STRINGS_EQUAL) ||
                (strcmp(argv[argNum],"-v")        == STRINGS_EQUAL)) {
                /* Print version information and exit. */
                PrintVersionInfo();
                exit(0);
            }

            else if ((strcmp(argv[argNum],"--help") == STRINGS_EQUAL) ||
                     (strcmp(argv[argNum],"-h")     == STRINGS_EQUAL) ||
                     (strcmp(argv[argNum],"-?")     == STRINGS_EQUAL)) {
                /* Print help information and exit. */
                PrintHelpInfo();
                exit(0);
            }

            else if ((strcmp(argv[argNum],"--file") == STRINGS_EQUAL) ||
                     (strcmp(argv[argNum],"-f")     == STRINGS_EQUAL)) {
                /* Set the name of the output file. */
                ++argNum;
                if (argNum < argc) {
                    SetFileName(argv[argNum]);
                }
                else {
                    printf("*** Output file name not specified. ***\n");
                    printf("Default output file name will be used.\n");
                }
            }

            else if ((strcmp(argv[argNum],"--time") == STRINGS_EQUAL) ||
                     (strcmp(argv[argNum],"-t")     == STRINGS_EQUAL)) {
                /* Set the interrupt period. */
                ++argNum;
                if (argNum < argc) {
                    SetInterruptPeriod(argv[argNum]);
                }
                else {
                    printf("*** Interrupt period not specified. ***\n");
                    printf("Default interrupt period will be used.\n");
                }

            }

            else if ((strcmp(argv[argNum],"--priority") ==
                      STRINGS_EQUAL) ||
                     (strcmp(argv[argNum],"-p")       == STRINGS_EQUAL)) {
                /* Set the scheduler priority. */
                ++argNum;
                if (argNum < argc) {
                    SetSchedulerPriority(argv[argNum]);
                }
                else {
                    printf("*** Scheduler priority not specified. ***\n");
                    printf("Default scheduler priority will be used.\n");
                }

            }

            else if ((strcmp(argv[argNum],"--readfile") ==
                      STRINGS_EQUAL) ||
                     (strcmp(argv[argNum],"-r")       == STRINGS_EQUAL)) {
                /* Set the file to read*/
                ++argNum;

                strncpy(ReadFile, argv[argNum], sizeof(ReadFile));
                DoRead = TRUE;
            }

            else if ((strcmp(argv[argNum],"--write_bytes") ==
                      STRINGS_EQUAL) ||
                     (strcmp(argv[argNum],"-w")       == STRINGS_EQUAL)) {
                /* Set the file to read*/
                ++argNum;

                WriteBytes = atoi(argv[argNum]);

                if(WriteBytes < MIN_WRITE_BYTES)
                {
                    printf("Writing less than %i bytes is not allowed. Bye.\n",
                           MIN_WRITE_BYTES);
                    exit(0);
                }


            }

            else if ((strcmp(argv[argNum],"--consolefile") ==
                      STRINGS_EQUAL) ||
                     (strcmp(argv[argNum],"-c")       == STRINGS_EQUAL)) {
	      /* Set the file to log console log on. */
	      ++argNum;

	      strncpy(LogFile, argv[argNum], sizeof(LogFile));
            }

            else if ((strcmp(argv[argNum],"--grab_kprofile") ==
                      STRINGS_EQUAL))
	      {
                /* We will read the /proc/profile file on configurable timeout */
                GrabKProfile = TRUE;

                ++argNum;

                /* If the jittter is > this #, then the profile is grabbed. */
                ProfileTriggerMSecs = (long) atoi(argv[argNum]);

		if(ProfileTriggerMSecs <= 0){

		  printf("Illegal value for profile trigger threshold.\n");
		  exit(0);
		}
	      }

            else if ((strcmp(argv[argNum],"--siggc") ==
                      STRINGS_EQUAL))
	      {
                /* We will SIGSTOP/SIGCONT the specified pid */
                SignalGCTask = TRUE;

                ++argNum;

                GCTaskPID = atoi(argv[argNum]);

		if(ProfileTriggerMSecs <= 0){

		  printf("Illegal value for JFFS(2) GC task pid.\n");
		  exit(0);
		}
	      }


            else {
	      /* Unknown argument. Print help information and exit. */
	      printf("Invalid option %s\n", argv[argNum]);
	      printf("Try 'JitterTest --help' for more information.\n");
	      exit(0);
            }
        }
    }

    return;
}


/***********************************************************************
 *                                SetFileName
 *  This function sets the output file name.
 *  output: N/A
 ***********************************************************************/
void SetFileName(
    char * pFileName)               /* ptr to desired output file name  */
{
    size_t fileNameLen;             /* file name length (bytes)         */

    /* Check file name length. */
    fileNameLen = strlen(pFileName);
    if (fileNameLen > (size_t) MAX_FILE_NAME_LEN) {
        printf("File name %s exceeds maximum length %d.\n",
               pFileName, MAX_FILE_NAME_LEN);
        exit(0);
    }

    /* File name length is OK so save the file name. */
    strcpy(OutFileName, pFileName);

    return;
}


/***********************************************************************
 *                             SetInterruptPeriod
 *  This function sets the interrupt period.
 *  output: N/A
 ***********************************************************************/
void SetInterruptPeriod(
    char *                          /* ptr to desired interrupt period  */
    pASCIIInterruptPeriodMilliSec)
{
    long period;                    /* interrupt period                 */

    period = atol(pASCIIInterruptPeriodMilliSec);
    if ((period < MIN_INT_PERIOD_MILLISEC) ||
        (period > MAX_INT_PERIOD_MILLISEC)) {
        printf("Invalid interrupt period: %ld ms.\n", period);
        exit(EXIT_INV_INT_PERIOD);
    }
    else {
        InterruptPeriodMilliSec = period;
    }
    return;
}


/***********************************************************************
 *                            SetSchedulerPriority
 *  This function sets the desired scheduler priority.
 *  output: N/A
 ***********************************************************************/
void SetSchedulerPriority(
    char * pASCIISchedulerPriority) /* ptr to desired scheduler priority*/
{
    int priority;                   /* desired scheduler priority value */

    priority = atoi(pASCIISchedulerPriority);
    if ((priority < MinPriority) ||
        (priority > MaxPriority)) {
        printf("Scheduler priority %d outside of range [%d, %d]\n",
               priority, MinPriority, MaxPriority);
        exit(EXIT_INV_SCHED_PRIORITY);
    }
    else {
        RequestedPriority = priority;
	RunAsRTTask = TRUE; /* We shall run as a POSIX real time task */
    }
    return;
}


/***********************************************************************
 *                              PrintVersionInfo
 *  This function prints version information.
 *  output: N/A
 ***********************************************************************/
void PrintVersionInfo(void)
{
    common_print_version();
    printf("Copyright (c) 2001, Daniel Industries, Inc.\n");
    return;
}


/***********************************************************************
 *                               PrintHelpInfo
 *  This function prints help information.
 *  output: N/A
 ***********************************************************************/
void PrintHelpInfo(void)
{
    printf("Usage: JitterTest [options]\n");
    printf("       *** Requires root privileges. ***\n");
    printf("Option:\n");
    printf("  [-h, --help, -?]           Print this message and exit.\n");
    printf("  [-v, --version]            ");
    printf(         "Print the version number of JitterTest and exit.\n");
    printf("  [-f FILE, --file FILE]     Set output file name to FILE. Typically you would put this on the fs under test\n");
    printf("  [-c FILE, --consolefile]   Set device or file to write the console log to.\n\tTypically you would set this to /dev/console and save it on another computer.\n");
    printf("  [-w BYTES, --write_bytes BYTES  Write BYTES to FILE each period.\n");
    printf("  [-r FILE, --readfile FILE]     Also read 1 byte every cycle from FILE. FILE will be created and filled with data.\n");
    printf("  [-t <n>, --time <n>]       ");
    printf(         "Set interrupt period to <n> milliseconds.\n");
    printf("                           ");
    printf(         "Range: [%ld, %ld] milliseconds.\n",
                    MIN_INT_PERIOD_MILLISEC, MAX_INT_PERIOD_MILLISEC);
    printf("  [-p <n>, --priority <n>]  ");
    printf(         "Set scheduler priority to <n>.\n");
    printf("                           ");
    printf(         "Range: [%d, %d] (higher number = higher priority)\n",
                    MinPriority, MaxPriority);
    printf("  [--grab_kprofile <THRESHOLD in ms>]    Read the /proc/profile if jitter is > THRESHOLD and store in file.\n");
    printf("  [--siggc <PID>]   Before writing to fs send SIGSTOP to PID. After write send SIGCONT\n");
    return;

}


/* A common write that checks for write errors and exits. Pass it __LINE__ for lineNo */
int Write(int fd, void *buf, size_t bytes, int lineNo)
{

    int err;

    err = write(fd, buf, bytes);

    if(err < bytes)
    {

        printf("Write Error at line %i! Wanted to write %zu bytes, but wrote only %i bytes.\n",
               lineNo, bytes, err);
        perror("Write did not complete. Error. Bye:"); /* show error from errno. */
	exit(1);

    }

    return err;

}/* end Write*/