That error is basically a segfault. What likely happened is that you're
program tried to read a member of a structure using a NULL pointer. The
pointer could have been NULL because the workload behaves incorrectly if
it's a custom benchmark for instance, or you're cache modifications are
making a load return all 0s when the pointer is accessed.
Gabe
sunitha p wrote:
> I am trying to partition L2 among the CPUs. Initially trying to make
> static logical partitioning among 4 CPUs
>
> have taken L2 as 8 way set associative and L1 as split 4 way set
> associative into consideration
>
> Hence, in each set , 2 blocks is assigned for each CPU. Since blocks
> are pointed by an array structure blks[],
>
> 0&1 - cpu1, 2&3 - cpu2 & so on
>
> in lru.cc, findVictim function finds the LRU block of the respective
> CPU. The code written is
>
> LRU::BlkType*
> LRU::findVictim(Addr addr, PacketList &writebacks,int cpu_id)
> {
> //int flag=0,flag_id=0;
> unsigned set = extractSet(addr);
> // grab a replacement candidate
> BlkType *blk;
>
> if(assoc==8) //implying its L2 cache
> {
> if(cpu_id==-1)
> cpu_id=3;
> int temp_position = 2*cpu_id+1;
>
> blk = sets[set].blks[temp_position];
>
> }
> else
> {
> blk=sets[set].blks[assoc-1];
> inform("L1 : set %x: selecting blk %x for replacement : CPU id
> : %d \n", set, regenerateBlkAddr(blk->tag, set),cpu_id);
> }
>
>
> if (blk->isValid())
> {
> replacements[0]++;
> totalRefs += blk->refCount;
> ++sampledRefs;
> blk->refCount = 0;
>
> // deal with evicted block
>
> if(blk->contextSrc!=-1)
> {
> occupancies[blk->contextSrc % cache->numCpus()]--;
> blk->contextSrc = -1;
> }
> else
> {
> occupancies[cache->numCpus()]--;
>
> }
> }
> DPRINTF(CacheRepl, "set %x: selecting blk %x for replacement\n",
> set, regenerateBlkAddr(blk->tag, set));
>
> return blk;
> }
>
> and in cacheSet.cc , moveHead() function- moves the block to the head
> position of respective CPU. The altered code is
>
> void
> CacheSet::moveToHead(CacheBlk *blk, int cpu_id)
> {
> int i;
>
> CacheBlk *next = blk;
> // nothing to do if blk is already head %d
> if(assoc==8 )
> {
> if(cpu_id==-1)
> cpu_id=3;
> if(blks[cpu_id*2]==blk)
> return;
> i = cpu_id* 2 ;
> while(i<(cpu_id) * 2 +2)
> {
> CacheBlk *tmp = blks[i];
> blks[i] = next;
> next = tmp;
>
> ++i;
> }
>
> }
> else
> {
> if (blks[0] == blk)
> return;
>
> do{
> assert(i<assoc);
> // swap blks[i] and next
>
> CacheBlk *tmp = blks[i];
> blks[i] = next;
> next = tmp;
>
> ++i;
> } while(next != blk);
> }
>
> }
>
>
> But i am getting mapping arror as
>
> panic: Tried to access unmapped address 0x58.
> @ cycle 25441428000
> [invoke:build/ALPHA_SE/arch/alpha/faults.cc, line 209]
> Memory Usage: 163640 KBytes
> For more information see: http://www.m5sim.org/panic/5932f339
> Program aborted at cycle 25441428000
> Aborted
>
>
> Can anyone kindly help as to what the error is and where i am making
> mistake
> --
> Sunitha.P
> 9092892876
>
> ------------------------------------------------------------------------
>
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