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/*---------------------------------------------------------------
* Copyright (c) 2019
* Broadcom Corporation
* All Rights Reserved.
*---------------------------------------------------------------
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated
* documentation files (the "Software"), to deal in the Software
* without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit
* persons to whom the Software is furnished to do
* so, subject to the following conditions:
*
*
* Redistributions of source code must retain the above
* copyright notice, this list of conditions and
* the following disclaimers.
*
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimers in the documentation and/or other materials
* provided with the distribution.
*
*
* Neither the name of Broadcom Coporation,
* nor the names of its contributors may be used to endorse
* or promote products derived from this Software without
* specific prior written permission.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE CONTIBUTORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
* ________________________________________________________________
*
* Suppport for packet rings between threads
*
* by Robert J. McMahon (rjmcmahon@rjmcmahon.com, bob.mcmahon@broadcom.com)
* -------------------------------------------------------------------
*/
#include "headers.h"
#include "packet_ring.h"
#include "Condition.h"
#include "Thread.h"
#ifdef HAVE_THREAD_DEBUG
#include "Mutex.h"
static int totalpacketringcount = 0;
Mutex packetringdebug_mutex;
#endif
struct PacketRing * packetring_init (int count, struct Condition *awake_consumer, struct Condition *awake_producer) {
assert(awake_consumer != NULL);
struct PacketRing *pr = NULL;
if ((pr = (struct PacketRing *) calloc(1, sizeof(struct PacketRing)))) {
pr->bytes = sizeof(struct PacketRing);
pr->data = (struct ReportStruct *) calloc(count, sizeof(struct ReportStruct));
pr->bytes += count * sizeof(struct ReportStruct);
}
if (!pr || !pr->data) {
fprintf(stderr, "ERROR: no memory for packet ring of size %d count, try to reduce with option --NUM_REPORT_STRUCTS\n", count);
exit(1);
}
pr->producer = 0;
pr->consumer = 0;
pr->maxcount = count;
pr->awake_producer = awake_producer;
pr->awake_consumer = awake_consumer;
if (!awake_producer)
pr->mutex_enable=0;
else
pr->mutex_enable=1;
pr->consumerdone = 0;
pr->awaitcounter = 0;
#ifdef HAVE_THREAD_DEBUG
Mutex_Lock(&packetringdebug_mutex);
totalpacketringcount++;
thread_debug("Init %d element packet ring=%p consumer=%p producer=%p total rings=%d enable=%d", count, \
(void *)pr, (void *) pr->awake_consumer, (void *) pr->awake_producer, totalpacketringcount, pr->mutex_enable);
Mutex_Unlock(&packetringdebug_mutex);
#endif
return (pr);
}
inline void packetring_enqueue (struct PacketRing *pr, struct ReportStruct *metapacket) {
while (((pr->producer == pr->maxcount) && (pr->consumer == 0)) || \
((pr->producer + 1) == pr->consumer)) {
// Signal the consumer thread to process a full queue
if (pr->mutex_enable) {
assert(pr->awake_consumer != NULL);
Condition_Signal(pr->awake_consumer);
// Wait for the consumer to create some queue space
assert(pr->awake_producer != NULL);
Condition_Lock((*(pr->awake_producer)));
pr->awaitcounter++;
#ifdef HAVE_THREAD_DEBUG_PERF
{
struct timeval now;
static struct timeval prev={0, 0};
gettimeofday( &now, NULL );
if (!prev.tv_sec || (TimeDifference(now, prev) > 1.0)) {
prev = now;
thread_debug( "Not good, traffic's packet ring %p stalled per %p", (void *)pr, (void *)&pr->awake_producer);
}
}
#endif
Condition_TimedWait(pr->awake_producer, 1);
Condition_Unlock((*(pr->awake_producer)));
}
}
int writeindex;
if ((pr->producer + 1) == pr->maxcount)
writeindex = 0;
else
writeindex = (pr->producer + 1);
/* Next two lines must be maintained as is */
memcpy((pr->data + writeindex), metapacket, sizeof(struct ReportStruct));
pr->producer = writeindex;
}
inline struct ReportStruct *packetring_dequeue (struct PacketRing *pr) {
struct ReportStruct *packet = NULL;
if (pr->producer == pr->consumer)
return NULL;
int readindex;
if ((pr->consumer + 1) == pr->maxcount)
readindex = 0;
else
readindex = (pr->consumer + 1);
packet = (pr->data + readindex);
// advance the consumer pointer last
pr->consumer = readindex;
if (pr->mutex_enable) {
// Signal the traffic thread assigned to this ring
// when the ring goes from having something to empty
if (pr->producer == pr->consumer) {
#ifdef HAVE_THREAD_DEBUG
// thread_debug( "Consumer signal packet ring %p empty per %p", (void *)pr, (void *)&pr->awake_producer);
#endif
assert(pr->awake_producer);
Condition_Signal(pr->awake_producer);
}
}
return packet;
}
inline void enqueue_ackring (struct PacketRing *pr, struct ReportStruct *metapacket) {
packetring_enqueue(pr, metapacket);
// Keep the latency low by signaling the consumer thread
// per each enqueue
#ifdef HAVE_THREAD_DEBUG
// thread_debug( "Producer signal consumer ackring=%p per %p", (void *)pr, (void *)&pr->awake_consumer);
#endif
Condition_Signal(pr->awake_consumer);
}
inline struct ReportStruct *dequeue_ackring (struct PacketRing *pr) {
struct ReportStruct *packet = NULL;
Condition_Lock((*(pr->awake_consumer)));
while ((packet = packetring_dequeue(pr)) == NULL) {
Condition_TimedWait(pr->awake_consumer, 1);
}
Condition_Unlock((*(pr->awake_consumer)));
if (packet) {
// Signal the producer thread for low latency
// indication of space available
Condition_Signal(pr->awake_producer);
}
return packet;
}
void packetring_free (struct PacketRing *pr) {
if (pr) {
if (pr->awaitcounter > 1000) fprintf(stderr, "WARN: Reporter thread may be too slow, await counter=%d, " \
"consider increasing NUM_REPORT_STRUCTS\n", pr->awaitcounter);
if (pr->data) {
#ifdef HAVE_THREAD_DEBUG
Mutex_Lock(&packetringdebug_mutex);
totalpacketringcount--;
thread_debug("Free packet ring=%p producer=%p (consumer=%p) awaits = %d total rings = %d", \
(void *)pr, (void *) pr->awake_producer, (void *) pr->awake_consumer, pr->awaitcounter, totalpacketringcount);
Mutex_Unlock(&packetringdebug_mutex);
#endif
free(pr->data);
}
free(pr);
}
}
void free_ackring(struct PacketRing *pr) {
packetring_free(pr);
Condition_Destroy(pr->awake_consumer);
}
/*
* This is an estimate and can be incorrect as these counters
* done like this is not thread safe. Use with care as there
* is no guarantee the return value is accurate
*/
#ifdef HAVE_THREAD_DEBUG
inline int packetring_getcount (struct PacketRing *pr) {
int depth = 0;
if (pr->producer != pr->consumer) {
depth = (pr->producer > pr->consumer) ? \
(pr->producer - pr->consumer) : \
((pr->maxcount - pr->consumer) + pr->producer);
// printf("DEBUG: Depth=%d for packet ring %p\n", depth, (void *)pr);
}
return depth;
}
#endif
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