From 2952390f27c07500bd2a24b5e6fdce5e282fc8dd Mon Sep 17 00:00:00 2001
From: Cedric Nugteren <web@cedricnugteren.nl>
Date: Fri, 29 Apr 2016 23:33:36 +0200
Subject: Added an example to demonstrate the use of the ClearCache and
 FillCache functions

---
 samples/cache.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 samples/cache.c

(limited to 'samples/cache.c')

diff --git a/samples/cache.c b/samples/cache.c
new file mode 100644
index 00000000..7f876be1
--- /dev/null
+++ b/samples/cache.c
@@ -0,0 +1,133 @@
+
+// =================================================================================================
+// This file is part of the CLBlast project. The project is licensed under Apache Version 2.0. This
+// project loosely follows the Google C++ styleguide and uses a tab-size of two spaces and a max-
+// width of 100 characters per line.
+//
+// Author(s):
+//   Cedric Nugteren <www.cedricnugteren.nl>
+//
+// This file demonstrates the CLBlast kernel cache, which stores compiled OpenCL binaries for faster
+// repeated kernel execution. The cache can be pre-initialized or cleared.
+//
+// Note that this example is meant for illustration purposes only. CLBlast provides other programs
+// for performance benchmarking ('client_xxxxx') and for correctness testing ('test_xxxxx').
+//
+// =================================================================================================
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+// Includes the CLBlast library (C interface)
+#include <clblast_c.h>
+
+// Forward declaration
+void run_example_routine(const cl_device_id device);
+
+// =================================================================================================
+
+// Example use of the CLBlast kernel cache
+int main(void) {
+
+  // OpenCL platform/device settings
+  const size_t platform_id = 0;
+  const size_t device_id = 0;
+
+  // Initializes the OpenCL platform
+  cl_uint num_platforms;
+  clGetPlatformIDs(0, NULL, &num_platforms);
+  cl_platform_id* platforms = (cl_platform_id*)malloc(num_platforms*sizeof(cl_platform_id));
+  clGetPlatformIDs(num_platforms, platforms, NULL);
+  cl_platform_id platform = platforms[platform_id];
+
+  // Initializes the OpenCL device
+  cl_uint num_devices;
+  clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, 0, NULL, &num_devices);
+  cl_device_id* devices = (cl_device_id*)malloc(num_devices*sizeof(cl_device_id));
+  clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, num_devices, devices, NULL);
+  cl_device_id device = devices[device_id];
+
+  // Run the routine multiple times in a row: after the first time the binary is already in the
+  // cache and compilation is no longer needed.
+  printf("Starting caching sample with an empty cache\n");
+  run_example_routine(device);
+  run_example_routine(device);
+  run_example_routine(device);
+
+  // Clearing the cache makes CLBlast re-compile the kernel once
+  printf("Clearing cache\n");
+  CLBlastClearCache();
+  run_example_routine(device);
+  run_example_routine(device);
+
+  // When the cache is empty, it can be pre-initialized with compiled kernels for all routines by
+  // calling the CLBlastFillCache function, such that all other CLBlast calls can benefit from
+  // pre-compiled kernels and thus execute at maximum speed.
+  printf("Clearing cache\n");
+  CLBlastClearCache();
+  printf("Filling cache (this might take a while)\n");
+  CLBlastFillCache(device);
+  run_example_routine(device);
+
+  // Clean-up
+  free(platforms);
+  free(devices);
+  return 0;
+}
+
+// =================================================================================================
+
+// Runs an example routine and reports the time
+void run_example_routine(const cl_device_id device) {
+
+  // Example SASUM arguments
+  const size_t n = 1024*128;
+
+  // Creates the OpenCL context, queue, and an event
+  cl_context context = clCreateContext(NULL, 1, &device, NULL, NULL, NULL);
+  cl_command_queue queue = clCreateCommandQueue(context, device, 0, NULL);
+  cl_event event = NULL;
+
+  // Populate host data structures with some example data
+  float* host_input = (float*)malloc(sizeof(float)*n);
+  float* host_output = (float*)malloc(sizeof(float)*1);
+  for (size_t i=0; i<n; ++i) { host_input[i] = -1.5f; }
+  for (size_t i=0; i<1; ++i) { host_output[i] = 0.0f; }
+
+  // Copy the data-structures to the device
+  cl_mem device_input = clCreateBuffer(context, CL_MEM_READ_WRITE, n*sizeof(float), NULL, NULL);
+  cl_mem device_output = clCreateBuffer(context, CL_MEM_READ_WRITE, 1*sizeof(float), NULL, NULL);
+  clEnqueueWriteBuffer(queue, device_input, CL_TRUE, 0, n*sizeof(float), host_input, 0, NULL, NULL);
+  clEnqueueWriteBuffer(queue, device_output, CL_TRUE, 0, 1*sizeof(float), host_output, 0, NULL, NULL);
+
+  // Start the timer
+  clock_t start = clock();
+
+  // Calls an example routine
+  StatusCode status = CLBlastSasum(n,
+                                   device_output, 0,
+                                   device_input, 0, 1,
+                                   &queue, &event);
+
+  // Wait for completion
+  clWaitForEvents(1, &event);
+
+  // Retrieves the execution time
+  clock_t diff = clock() - start;
+  double time_ms = diff * 1000.0f / (double)CLOCKS_PER_SEC;
+
+  // Routine completed. See "clblast_c.h" for status codes (0 -> success).
+  printf("Completed routine with status %d in %.3lf ms\n", status, time_ms);
+
+  // Clean-up
+  free(host_input);
+  free(host_output);
+  clReleaseMemObject(device_input);
+  clReleaseMemObject(device_output);
+  clReleaseCommandQueue(queue);
+  clReleaseContext(context);
+}
+
+// =================================================================================================
-- 
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