tor-browser

switch.cpp (6834B)

---

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
** File:            switch.cpp
** Description:     trying to time context switches
*/

#include "rccv.h"
#include "rcinrval.h"
#include "rclock.h"
#include "rcthread.h"

#include <prio.h>
#include <prlog.h>
#include <prprf.h>
#include <plerror.h>
#include <plgetopt.h>

#include <stdlib.h>

#define INNER_LOOPS 100
#define DEFAULT_LOOPS 100
#define DEFAULT_THREADS 10

static PRFileDesc *debug_out = NULL;
static PRBool debug_mode = PR_FALSE, verbosity = PR_FALSE, failed = PR_FALSE;

class Home: public RCCondition
{
public:
   virtual ~Home();
   Home(Home *link, RCLock* ml);

public:
   Home *next;
   RCLock* ml;
   PRBool twiddle;
};  /* Home */

Home::~Home() { }

Home::Home(Home *link, RCLock* lock): RCCondition(lock)
{
   ml = lock;
   next = link;
   twiddle = PR_FALSE;
}  /* Home::Home */

class Shared: public Home, public RCThread
{
public:
   Shared(RCThread::Scope scope, Home* link, RCLock* ml);

private:
   ~Shared();
   void RootFunction();
};  /* Shared */

Shared::Shared(RCThread::Scope scope, Home* link, RCLock* lock):
   Home(link, lock), RCThread(scope, RCThread::joinable) { }

Shared::~Shared() { }

void Shared::RootFunction()
{
   PRStatus status = PR_SUCCESS;
   while (PR_SUCCESS == status)
   {
       RCEnter entry(ml);
       while (twiddle && (PR_SUCCESS == status)) {
           status = Wait();
       }
       if (verbosity) {
           PR_fprintf(debug_out, "+");
       }
       twiddle = PR_TRUE;
       next->twiddle = PR_FALSE;
       next->Notify();
   }
}  /* Shared::RootFunction */

static void Help(void)
{
   debug_out = PR_STDOUT;

   PR_fprintf(
       debug_out, "Usage: >./switch [-d] [-c n] [-t n] [-T n] [-G]\n");
   PR_fprintf(
       debug_out, "-c n\tloops at thread level (default: %d)\n", DEFAULT_LOOPS);
   PR_fprintf(
       debug_out, "-t n\tnumber of threads (default: %d)\n", DEFAULT_THREADS);
   PR_fprintf(debug_out, "-d\tturn on debugging output (default: FALSE)\n");
   PR_fprintf(debug_out, "-v\tturn on verbose output (default: FALSE)\n");
   PR_fprintf(debug_out, "-G n\tglobal threads only (default: FALSE)\n");
   PR_fprintf(debug_out, "-C n\tconcurrency setting (default: 1)\n");
}  /* Help */

PRIntn main(PRIntn argc, char **argv)
{
   PLOptStatus os;
   PRStatus status;
   PRBool help = PR_FALSE;
   PRUintn concurrency = 1;
   RCThread::Scope thread_scope = RCThread::local;
   PRUintn thread_count, inner_count, loop_count, average;
   PRUintn thread_limit = DEFAULT_THREADS, loop_limit = DEFAULT_LOOPS;
   PLOptState *opt = PL_CreateOptState(argc, argv, "hdvc:t:C:G");
   while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))
   {
       if (PL_OPT_BAD == os) {
           continue;
       }
       switch (opt->option)
       {
           case 'v':  /* verbose mode */
               verbosity = PR_TRUE;
           case 'd':  /* debug mode */
               debug_mode = PR_TRUE;
               break;
           case 'c':  /* loop counter */
               loop_limit = atoi(opt->value);
               break;
           case 't':  /* thread limit */
               thread_limit = atoi(opt->value);
               break;
           case 'C':  /* Concurrency limit */
               concurrency = atoi(opt->value);
               break;
           case 'G':  /* global threads only */
               thread_scope = RCThread::global;
               break;
           case 'h':  /* help message */
               Help();
               help = PR_TRUE;
               break;
           default:
               break;
       }
   }
   PL_DestroyOptState(opt);

   if (help) {
       return -1;
   }

   if (PR_TRUE == debug_mode)
   {
       debug_out = PR_STDOUT;
       PR_fprintf(debug_out, "Test parameters\n");
       PR_fprintf(debug_out, "\tThreads involved: %d\n", thread_limit);
       PR_fprintf(debug_out, "\tIteration limit: %d\n", loop_limit);
       PR_fprintf(debug_out, "\tConcurrency: %d\n", concurrency);
       PR_fprintf(
           debug_out, "\tThread type: %s\n",
           (PR_GLOBAL_THREAD == thread_scope) ? "GLOBAL" : "LOCAL");
   }

   /*
   ** The interesting part starts here
   */
   RCLock lock;
   Shared* shared;
   Home home(NULL, &lock);
   Home* link = &home;
   RCInterval timein, timeout = 0;

   /* Build up the string of objects */
   for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
   {
       shared = new Shared(thread_scope, link, &lock);
       shared->Start();  /* make it run */
       link = (Home*)shared;
   }

   /* Pass the message around the horn a few times */
   for (loop_count = 1; loop_count <= loop_limit; ++loop_count)
   {
       timein.SetToNow();
       for (inner_count = 0; inner_count < INNER_LOOPS; ++inner_count)
       {
           RCEnter entry(&lock);
           home.twiddle = PR_TRUE;
           shared->twiddle = PR_FALSE;
           shared->Notify();
           while (home.twiddle)
           {
               failed = (PR_FAILURE == home.Wait()) ? PR_TRUE : PR_FALSE;
           }
       }
       timeout += (RCInterval(RCInterval::now) - timein);
   }

   /* Figure out how well we did */
   if (debug_mode)
   {
       average = timeout.ToMicroseconds()
                 / (INNER_LOOPS * loop_limit * thread_count);
       PR_fprintf(
           debug_out, "Average switch times %d usecs for %d threads\n",
           average, thread_limit);
   }

   /* Start reclamation process */
   link = shared;
   for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
   {
       if (&home == link) {
           break;
       }
       status = ((Shared*)link)->Interrupt();
       if (PR_SUCCESS != status)
       {
           failed = PR_TRUE;
           if (debug_mode) {
               PL_FPrintError(debug_out, "Failed to interrupt");
           }
       }
       link = link->next;
   }

   for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
   {
       link = shared->next;
       status = shared->Join();
       if (PR_SUCCESS != status)
       {
           failed = PR_TRUE;
           if (debug_mode) {
               PL_FPrintError(debug_out, "Failed to join");
           }
       }
       if (&home == link) {
           break;
       }
       shared = (Shared*)link;
   }

   PR_fprintf(PR_STDOUT, ((failed) ? "FAILED\n" : "PASSED\n"));

   failed |= (PR_SUCCESS == RCPrimordialThread::Cleanup());

   return ((failed) ? 1 : 0);
}  /* main */

/* switch.c */