Add a README and tests for stream masking and next masking

Also rewrite the global masking test to be much more thorough.

1 files changed, 140 insertions, 0 deletions

diff --git a/libsmctrl_test_mask_shared.cu b/libsmctrl_test_mask_shared.cu
new file mode 100644
index 0000000..c3817fa
--- /dev/null
+++ b/libsmctrl_test_mask_shared.cu
@@ -0,0 +1,140 @@
+// Copyright 2023 Joshua Bakita
+#include <error.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <cuda_runtime.h>
+
+#include "libsmctrl.h"
+#include "testbench.h"
+#include "libsmctrl_test_mask_shared.h"
+
+__global__ void read_and_store_smid(uint8_t* smid_arr) {
+  if (threadIdx.x != 1)
+    return;
+  int smid;
+  asm("mov.u32 %0, %%smid;" : "=r"(smid));
+  smid_arr[blockIdx.x] = smid;
+}
+
+// Assuming SMs continue to support a maximum of 2048 resident threads, six
+// blocks of 1024 threads should span at least three SMs without partitioning
+#define NUM_BLOCKS 142 //6
+
+static int sort_asc(const void* a, const void* b) {
+  return *(uint8_t*)a - *(uint8_t*)b;
+}
+
+// Warning: Mutates input array via qsort
+static int count_unique(uint8_t* arr, int len) {
+  qsort(arr, len, 1, sort_asc);
+  int num_uniq = 1;
+  for (int i = 0; i < len - 1; i++)
+    num_uniq += (arr[i] != arr[i + 1]);
+  return num_uniq;
+}
+
+// Test that adding an SM mask:
+// 1. Constrains the number of SMs accessible
+// 2. Constrains an application to the correct subset of SMs
+int test_constrained_size_and_location(enum partitioning_type part_type) {
+  int res;
+  uint8_t *smids_native_d, *smids_native_h;
+  uint8_t *smids_partitioned_d, *smids_partitioned_h;
+  int uniq_native, uniq_partitioned;
+  uint32_t num_tpcs;
+  int num_sms, sms_per_tpc;
+  cudaStream_t stream;
+
+  SAFE(cudaStreamCreate(&stream));
+
+  // Determine number of SMs per TPC
+  SAFE(cudaDeviceGetAttribute(&num_sms, cudaDevAttrMultiProcessorCount, 0));
+  if (res = libsmctrl_get_tpc_info_cuda(&num_tpcs, 0))
+    error(1, res, "Unable to get TPC configuration for test");
+  sms_per_tpc = num_sms/num_tpcs;
+
+  // Test baseline (native) behavior without partitioning
+  SAFE(cudaMalloc(&smids_native_d, NUM_BLOCKS));
+  if (!(smids_native_h = (uint8_t*)malloc(NUM_BLOCKS)))
+    error(1, errno, "Unable to allocate memory for test");
+  read_and_store_smid<<<NUM_BLOCKS, 1024, 0, stream>>>(smids_native_d);
+  SAFE(cudaMemcpy(smids_native_h, smids_native_d, NUM_BLOCKS, cudaMemcpyDeviceToHost));
+
+  uniq_native = count_unique(smids_native_h, NUM_BLOCKS);
+  if (uniq_native < sms_per_tpc) {
+    printf("%s: ***Test failure.***\n"
+           "%s: Reason: In baseline test, %d blocks of 1024 "
+           "threads were launched on the GPU, but only %d SMs were utilized, "
+           "when it was expected that at least %d would be used.\n", program_invocation_name, program_invocation_name, NUM_BLOCKS,
+           uniq_native, sms_per_tpc);
+    return 1;
+  }
+
+  // Test at 32-TPC boundaries to verify that the mask is applied in the
+  // correct order to each of the QMD/stream struct fields.
+  char* reason[4] = {0};
+  for (int enabled_tpc = 0; enabled_tpc < num_tpcs && enabled_tpc < 128; enabled_tpc += 32) {
+    uint128_t mask = 1;
+    mask <<= enabled_tpc;
+    mask = ~mask;
+
+    // Apply partitioning to enable only the first TPC of each 32-bit block
+    switch (part_type) {
+      case PARTITION_GLOBAL:
+        libsmctrl_set_global_mask(mask);
+        break;
+      case PARTITION_STREAM:
+        libsmctrl_set_stream_mask_ext(stream, mask);
+        break;
+      case PARTITION_NEXT:
+        libsmctrl_set_next_mask(mask);
+        break;
+      default:
+        error(1, 0, "Shared test core called with unrecognized partitioning type.");
+    }
+
+    // Verify that partitioning changes the SMID distribution
+    SAFE(cudaMalloc(&smids_partitioned_d, NUM_BLOCKS));
+    if (!(smids_partitioned_h = (uint8_t*)malloc(NUM_BLOCKS)))
+      error(1, errno, "Unable to allocate memory for test");
+    read_and_store_smid<<<NUM_BLOCKS, 1024, 0, stream>>>(smids_partitioned_d);
+    SAFE(cudaMemcpy(smids_partitioned_h, smids_partitioned_d, NUM_BLOCKS, cudaMemcpyDeviceToHost));
+
+    // Make sure it only ran on the number of TPCs provided
+    // May run on up to two SMs, as up to two per TPC
+    uniq_partitioned = count_unique(smids_partitioned_h, NUM_BLOCKS); // Sorts too
+    if (uniq_partitioned > sms_per_tpc) {
+      printf("%s: ***Test failure.***\n"
+             "%s: Reason: With TPC mask set to "
+             "constrain all kernels to a single TPC, a kernel of %d blocks of "
+             "1024 threads was launched and found to run on %d SMs (at most %d---"
+             "one TPC---expected).\n", program_invocation_name, program_invocation_name, NUM_BLOCKS, uniq_partitioned, sms_per_tpc);
+      return 1;
+    }
+
+    // Make sure it ran on the right TPC
+    if (smids_partitioned_h[NUM_BLOCKS - 1] > (enabled_tpc * sms_per_tpc) + sms_per_tpc - 1 ||
+        smids_partitioned_h[NUM_BLOCKS - 1] < (enabled_tpc * sms_per_tpc)) {
+      printf("%s: ***Test failure.***\n"
+             "%s: Reason: With TPC mask set to"
+             "constrain all kernels to TPC %d, a kernel was run and found "
+             "to run on an SM IDs: as high as %d and as low as %d (range of %d to %d expected).\n",
+             program_invocation_name, program_invocation_name, enabled_tpc, smids_partitioned_h[NUM_BLOCKS - 1], smids_partitioned_h[0], enabled_tpc * sms_per_tpc + sms_per_tpc - 1, enabled_tpc * sms_per_tpc);
+      return 1;
+    }
+
+    // Div by 32 via a shift
+    asprintf(&reason[enabled_tpc >> 5],
+         "With a partition enabled which "
+         "contained only TPC ID %d, the test kernel was found to use only %d "
+         "SMs (%d without), and all SMs in-use had IDs between %d and %d (were contained"
+         " in TPC %d).", enabled_tpc, uniq_partitioned, uniq_native, smids_partitioned_h[0], smids_partitioned_h[NUM_BLOCKS - 1], enabled_tpc);
+  }
+
+  printf("%s: Test passed!\n", program_invocation_name);
+  for (int i = 0; i < 4 && reason[i]; i++)
+    printf("%s: Reason %d: %s\n", program_invocation_name, i + 1, reason[i]);
+  return 0;
+}
+