diff --git a/doc/tuning.md b/doc/tuning.md
index 474553b4cb2900ca20b899b70059e5cd57eb1fb0..25c50655decf94ac691c7d4bb809b39a96efd0ba 100644
--- a/doc/tuning.md
+++ b/doc/tuning.md
@@ -8,6 +8,7 @@
* [Choose `intensity` and `worksize`](#choose-intensity-and-worksize)
* [Add more GPUs](#add-more-gpus)
* [Increase Memory Pool](#increase-memory-pool)
+ * [Scratchpad Indexing](#scratchpad-indexing)
## NVIDIA Backend
@@ -80,4 +81,9 @@ export GPU_MAX_ALLOC_PERCENT=99
export GPU_SINGLE_ALLOC_PERCENT=99
```
-*Note:* Windows user must use `set` instead of `export` to define an environment variable.
\ No newline at end of file
+*Note:* Windows user must use `set` instead of `export` to define an environment variable.
+
+### Scratchpad Indexing
+
+The layout of the hash scratchpad memory can be changed for each GPU with the option `strided_index` in `amd.txt`.
+Try to change the value from the default `false` to `true`.
diff --git a/xmrstak/backend/amd/amd_gpu/gpu.cpp b/xmrstak/backend/amd/amd_gpu/gpu.cpp
index 879a2e4caa9f219f6355018f3b4d24a6191a6018..42f63884729eb9ea7185b44b7bbcd63648d00f9a 100644
--- a/xmrstak/backend/amd/amd_gpu/gpu.cpp
+++ b/xmrstak/backend/amd/amd_gpu/gpu.cpp
@@ -332,7 +332,8 @@ size_t InitOpenCLGpu(cl_context opencl_ctx, GpuContext* ctx, const char* source_
char options[256];
snprintf(options, sizeof(options),
- "-DITERATIONS=%d -DMASK=%d -DWORKSIZE=%llu", hasIterations, threadMemMask, int_port(ctx->workSize));
+ "-DITERATIONS=%d -DMASK=%d -DWORKSIZE=%llu -DSTRIDED_INDEX=%d",
+ hasIterations, threadMemMask, int_port(ctx->workSize), ctx->stridedIndex ? 1 : 0);
ret = clBuildProgram(ctx->Program, 1, &ctx->DeviceID, options, NULL, NULL);
if(ret != CL_SUCCESS)
{
diff --git a/xmrstak/backend/amd/amd_gpu/gpu.hpp b/xmrstak/backend/amd/amd_gpu/gpu.hpp
index abbd08d2f7edbaeadede8fc81ec806afdb5c80ef..c17bac11b0e998faa4315d6028c279c83c7ca0a1 100644
--- a/xmrstak/backend/amd/amd_gpu/gpu.hpp
+++ b/xmrstak/backend/amd/amd_gpu/gpu.hpp
@@ -24,6 +24,7 @@ struct GpuContext
size_t deviceIdx;
size_t rawIntensity;
size_t workSize;
+ int stridedIndex;
/*Output vars*/
cl_device_id DeviceID;
diff --git a/xmrstak/backend/amd/amd_gpu/opencl/cryptonight.cl b/xmrstak/backend/amd/amd_gpu/opencl/cryptonight.cl
index 966199bc418bd2a65ccbaec1012508b061fca8c2..255fcbbff79becb419a605b808bddfdcb798e2f3 100644
--- a/xmrstak/backend/amd/amd_gpu/opencl/cryptonight.cl
+++ b/xmrstak/backend/amd/amd_gpu/opencl/cryptonight.cl
@@ -411,7 +411,11 @@ void AESExpandKey256(uint *keybuf)
}
}
-#define IDX(x) (x)
+#if(STRIDED_INDEX==0)
+# define IDX(x) (x)
+#else
+# define IDX(x) ((x) * (Threads))
+#endif
__attribute__((reqd_work_group_size(WORKSIZE, 8, 1)))
__kernel void cn0(__global ulong *input, __global uint4 *Scratchpad, __global ulong *states, ulong Threads)
@@ -440,7 +444,12 @@ __kernel void cn0(__global ulong *input, __global uint4 *Scratchpad, __global ul
if(gIdx < Threads)
{
states += 25 * gIdx;
+
+#if(STRIDED_INDEX==0)
Scratchpad += gIdx * (ITERATIONS >> 2);
+#else
+ Scratchpad += gIdx;
+#endif
((ulong8 *)State)[0] = vload8(0, input);
State[8] = input[8];
@@ -519,7 +528,11 @@ __kernel void cn1(__global uint4 *Scratchpad, __global ulong *states, ulong Thre
if(gIdx < Threads)
{
states += 25 * gIdx;
+#if(STRIDED_INDEX==0)
Scratchpad += gIdx * (ITERATIONS >> 2);
+#else
+ Scratchpad += gIdx;
+#endif
a[0] = states[0] ^ states[4];
b[0] = states[2] ^ states[6];
@@ -588,7 +601,11 @@ __kernel void cn2(__global uint4 *Scratchpad, __global ulong *states, __global u
if(gIdx < Threads)
{
states += 25 * gIdx;
+#if(STRIDED_INDEX==0)
Scratchpad += gIdx * (ITERATIONS >> 2);
+#else
+ Scratchpad += gIdx;
+#endif
#if defined(__Tahiti__) || defined(__Pitcairn__)
diff --git a/xmrstak/backend/amd/autoAdjust.hpp b/xmrstak/backend/amd/autoAdjust.hpp
index 0b91212cbf5350bc18373772086e3919201d91e8..0abf84e837bbd434cea63f847ab1bd179baa8192 100644
--- a/xmrstak/backend/amd/autoAdjust.hpp
+++ b/xmrstak/backend/amd/autoAdjust.hpp
@@ -123,7 +123,7 @@ private:
// set 8 threads per block (this is a good value for the most gpus)
conf += std::string(" { \"index\" : ") + std::to_string(ctx.deviceIdx) + ",\n" +
" \"intensity\" : " + std::to_string(intensity) + ", \"worksize\" : " + std::to_string(8) + ",\n" +
- " \"affine_to_cpu\" : false, \n"
+ " \"affine_to_cpu\" : false, \"strided_index\" : false\n"
" },\n";
++i;
}
diff --git a/xmrstak/backend/amd/config.tpl b/xmrstak/backend/amd/config.tpl
index a93859cdf013a6439c99c858df0110df5a9aed33..f31a678faf281525c443727801dc009b978a370e 100644
--- a/xmrstak/backend/amd/config.tpl
+++ b/xmrstak/backend/amd/config.tpl
@@ -5,9 +5,12 @@ R"===(
* intensity - Number of parallel GPU threads (nothing to do with CPU threads)
* worksize - Number of local GPU threads (nothing to do with CPU threads)
* affine_to_cpu - This will affine the thread to a CPU. This can make a GPU miner play along nicer with a CPU miner.
+ * strided_index - switch memory pattern used for the scratch pad memory
+ * false = use a contiguous block of memory per thread
+ * true = use 16byte contiguous memory per thread, the next memory block has offset of intensity blocks
* "gpu_threads_conf" :
* [
- * { "index" : 0, "intensity" : 1000, "worksize" : 8, "affine_to_cpu" : false },
+ * { "index" : 0, "intensity" : 1000, "worksize" : 8, "affine_to_cpu" : false, "strided_index" : false },
* ],
*/
diff --git a/xmrstak/backend/amd/jconf.cpp b/xmrstak/backend/amd/jconf.cpp
index 0617aeb2fe3c78e4164d3a632173a6f110ca6f97..07afb1964d2a943cc1b2c0e8148ff5aa578b2a9a 100644
--- a/xmrstak/backend/amd/jconf.cpp
+++ b/xmrstak/backend/amd/jconf.cpp
@@ -103,13 +103,14 @@ bool jconf::GetThreadConfig(size_t id, thd_cfg &cfg)
if(!oThdConf.IsObject())
return false;
- const Value *idx, *intensity, *w_size, *aff;
+ const Value *idx, *intensity, *w_size, *aff, *stridedIndex;
idx = GetObjectMember(oThdConf, "index");
intensity = GetObjectMember(oThdConf, "intensity");
w_size = GetObjectMember(oThdConf, "worksize");
aff = GetObjectMember(oThdConf, "affine_to_cpu");
+ stridedIndex = GetObjectMember(oThdConf, "strided_index");
- if(idx == nullptr || intensity == nullptr || w_size == nullptr || aff == nullptr)
+ if(idx == nullptr || intensity == nullptr || w_size == nullptr || aff == nullptr || stridedIndex == nullptr)
return false;
if(!idx->IsUint64() || !intensity->IsUint64() || !w_size->IsUint64())
@@ -118,9 +119,13 @@ bool jconf::GetThreadConfig(size_t id, thd_cfg &cfg)
if(!aff->IsUint64() && !aff->IsBool())
return false;
+ if(!stridedIndex->IsBool())
+ return false;
+
cfg.index = idx->GetUint64();
cfg.intensity = intensity->GetUint64();
cfg.w_size = w_size->GetUint64();
+ cfg.stridedIndex = stridedIndex->GetBool();
if(aff->IsNumber())
cfg.cpu_aff = aff->GetInt64();
diff --git a/xmrstak/backend/amd/jconf.hpp b/xmrstak/backend/amd/jconf.hpp
index da024a412246c17a4df8041b081c7fe03fa7776a..ee1882aad754ba32840d959f1c44f255f1af0380 100644
--- a/xmrstak/backend/amd/jconf.hpp
+++ b/xmrstak/backend/amd/jconf.hpp
@@ -26,6 +26,7 @@ public:
size_t intensity;
size_t w_size;
long long cpu_aff;
+ bool stridedIndex;
};
size_t GetThreadCount();
diff --git a/xmrstak/backend/amd/minethd.cpp b/xmrstak/backend/amd/minethd.cpp
index c1399e0b8adef5220177168888857f3f428b3e48..103688f8a1f7327e62921c8a9b8568123a0552f5 100644
--- a/xmrstak/backend/amd/minethd.cpp
+++ b/xmrstak/backend/amd/minethd.cpp
@@ -96,6 +96,7 @@ bool minethd::init_gpus()
vGpuData[i].deviceIdx = cfg.index;
vGpuData[i].rawIntensity = cfg.intensity;
vGpuData[i].workSize = cfg.w_size;
+ vGpuData[i].stridedIndex = cfg.stridedIndex;
}
return InitOpenCL(vGpuData.data(), n, jconf::inst()->GetPlatformIdx()) == ERR_SUCCESS;