Significance of printf in memory throughput test

Firstly, there is printf() and System_printf().  I'm not sure what printf() might do outside of CCS, but in CCS, it works with breakpoints -- and that should theoretically provide almost no overhead or effect on the program.  System_printf() is the "normal" printf in that it writes to a buffer that gets printed out later.  Using System_printf() might reduce overhead.

Also, I myself noted that even though printf() doesn't necessarily affect the results of the code, in my particular experience, it can temporarily use a lot of resources -- but it shouldn't have a lasting effect (e.g.  multiple tests, but it shouldn't affect the first one much either)

I myself have written a core-synchronization code in software that I've found pretty useful (it's not intended to be very high performance, but it does synchronize cores). It uses BIOS and IPC -- but if you cannot use them, then IPC's MultiProc could be replaced by any sort of core-identifier.. although BIOS's Cache routines would need to be replaced with writing into the cache-invalidation/writeback registers (which CSL could certainly help with)

#include <ti/ipc/MultiProc.h>

#include <ti/sysbios/hal/Cache.h>

// As a global variable

#pragma DATA_SECTION(syncLine, ".myMSMC")

int syncLine[8] = {0,0,0,0, 0,0,0,0};

void barrierSync() {

int clusterSize = MultiProc_getNumProcessors();

int clusterBaseId = 0;

int selfId = MultiProc_self();

int i;

Cache_inv(syncLine, sizeof(int)*8, Cache_Type_ALL, TRUE);

for(i = 0; i < clusterSize; ) {

if (i == (selfId - clusterBaseId)) {

syncLine[i] = 1;

Cache_wbInv(syncLine, sizeof(int)*8, Cache_Type_ALL, TRUE);

++i;

}

if (syncLine[i] == 1) {

++i;

}

Cache_inv(syncLine, sizeof(int)*8, Cache_Type_ALL, TRUE);

}

for(i = 0; i < clusterSize; ) {

if (i == (selfId - clusterBaseId)) {

syncLine[i] = 0;

Cache_wbInv(syncLine, sizeof(int)*8, Cache_Type_ALL, TRUE);

++i;

}

if (syncLine[i] == 0) {

++i;

}

Cache_inv(syncLine, sizeof(int)*8, Cache_Type_ALL, TRUE);

}

}

And then put in the linker file (create a file named "lnk.cmd")

SECTIONS

{

.myMSMC > MSMCSRAM

}