/* StarPU --- Runtime system for heterogeneous multicore architectures. * * Copyright (C) 2010-2014 Université de Bordeaux 1 * Copyright (C) 2010, 2011, 2012, 2013, 2014 Centre National de la Recherche Scientifique * * StarPU is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or (at * your option) any later version. * * StarPU is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * * See the GNU Lesser General Public License in COPYING.LGPL for more details. */ #include #include #include #include #include #include #include #include #include #include #include #ifdef STARPU_USE_CUDA static int copy_ram_to_cuda(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED); static int copy_cuda_to_ram(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED); static int copy_cuda_to_cuda(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED); static int copy_ram_to_cuda_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cudaStream_t stream); static int copy_cuda_to_ram_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cudaStream_t stream); static int copy_cuda_to_cuda_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cudaStream_t stream); #endif #ifdef STARPU_USE_OPENCL static int copy_ram_to_opencl(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED); static int copy_opencl_to_ram(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED); static int copy_opencl_to_opencl(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED); static int copy_ram_to_opencl_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cl_event *event); static int copy_opencl_to_ram_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cl_event *event); static int copy_opencl_to_opencl_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cl_event *event); #endif static int copy_any_to_any(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, void *async_data); static const struct starpu_data_copy_methods matrix_copy_data_methods_s = { #ifdef STARPU_USE_CUDA .ram_to_cuda = copy_ram_to_cuda, .cuda_to_ram = copy_cuda_to_ram, .ram_to_cuda_async = copy_ram_to_cuda_async, .cuda_to_ram_async = copy_cuda_to_ram_async, .cuda_to_cuda = copy_cuda_to_cuda, .cuda_to_cuda_async = copy_cuda_to_cuda_async, #else #ifdef STARPU_SIMGRID /* Enable GPU-GPU transfers in simgrid */ .cuda_to_cuda_async = 1, #endif #endif #ifdef STARPU_USE_OPENCL .ram_to_opencl = copy_ram_to_opencl, .opencl_to_ram = copy_opencl_to_ram, .opencl_to_opencl = copy_opencl_to_opencl, .ram_to_opencl_async = copy_ram_to_opencl_async, .opencl_to_ram_async = copy_opencl_to_ram_async, .opencl_to_opencl_async = copy_opencl_to_opencl_async, #endif .any_to_any = copy_any_to_any, }; static void register_matrix_handle(starpu_data_handle_t handle, unsigned home_node, void *data_interface); static void *matrix_handle_to_pointer(starpu_data_handle_t data_handle, unsigned node); static starpu_ssize_t allocate_matrix_buffer_on_node(void *data_interface_, unsigned dst_node); static void free_matrix_buffer_on_node(void *data_interface, unsigned node); static size_t matrix_interface_get_size(starpu_data_handle_t handle); static uint32_t footprint_matrix_interface_crc32(starpu_data_handle_t handle); static int matrix_compare(void *data_interface_a, void *data_interface_b); static void display_matrix_interface(starpu_data_handle_t handle, FILE *f); static int pack_matrix_handle(starpu_data_handle_t handle, unsigned node, void **ptr, ssize_t *count); static int unpack_matrix_handle(starpu_data_handle_t handle, unsigned node, void *ptr, size_t count); static ssize_t describe(void *data_interface, char *buf, size_t size); struct starpu_data_interface_ops starpu_interface_matrix_ops = { .register_data_handle = register_matrix_handle, .allocate_data_on_node = allocate_matrix_buffer_on_node, .handle_to_pointer = matrix_handle_to_pointer, .free_data_on_node = free_matrix_buffer_on_node, .copy_methods = &matrix_copy_data_methods_s, .get_size = matrix_interface_get_size, .footprint = footprint_matrix_interface_crc32, .compare = matrix_compare, .interfaceid = STARPU_MATRIX_INTERFACE_ID, .interface_size = sizeof(struct starpu_matrix_interface), .display = display_matrix_interface, .pack_data = pack_matrix_handle, .unpack_data = unpack_matrix_handle, .describe = describe }; static void register_matrix_handle(starpu_data_handle_t handle, unsigned home_node, void *data_interface) { struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) data_interface; unsigned node; for (node = 0; node < STARPU_MAXNODES; node++) { struct starpu_matrix_interface *local_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, node); if (node == home_node) { local_interface->ptr = matrix_interface->ptr; local_interface->dev_handle = matrix_interface->dev_handle; local_interface->offset = matrix_interface->offset; local_interface->ld = matrix_interface->ld; } else { local_interface->ptr = 0; local_interface->dev_handle = 0; local_interface->offset = 0; local_interface->ld = 0; } local_interface->id = matrix_interface->id; local_interface->nx = matrix_interface->nx; local_interface->ny = matrix_interface->ny; local_interface->elemsize = matrix_interface->elemsize; } } static void *matrix_handle_to_pointer(starpu_data_handle_t handle, unsigned node) { STARPU_ASSERT(starpu_data_test_if_allocated_on_node(handle, node)); struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, node); return (void*) matrix_interface->ptr; } /* declare a new data with the matrix interface */ void starpu_matrix_data_register(starpu_data_handle_t *handleptr, unsigned home_node, uintptr_t ptr, uint32_t ld, uint32_t nx, uint32_t ny, size_t elemsize) { struct starpu_matrix_interface matrix_interface = { .id = STARPU_MATRIX_INTERFACE_ID, .ptr = ptr, .ld = ld, .nx = nx, .ny = ny, .elemsize = elemsize, .dev_handle = ptr, .offset = 0 }; #ifdef STARPU_USE_SCC _starpu_scc_set_offset_in_shared_memory((void*)matrix_interface.ptr, (void**)&(matrix_interface.dev_handle), &(matrix_interface.offset)); #endif starpu_data_register(handleptr, home_node, &matrix_interface, &starpu_interface_matrix_ops); } void starpu_matrix_ptr_register(starpu_data_handle_t handle, unsigned node, uintptr_t ptr, uintptr_t dev_handle, size_t offset, uint32_t ld) { struct starpu_matrix_interface *matrix_interface = starpu_data_get_interface_on_node(handle, node); starpu_data_ptr_register(handle, node); matrix_interface->ptr = ptr; matrix_interface->dev_handle = dev_handle; matrix_interface->offset = offset; matrix_interface->ld = ld; } static uint32_t footprint_matrix_interface_crc32(starpu_data_handle_t handle) { return starpu_hash_crc32c_be(starpu_matrix_get_nx(handle), starpu_matrix_get_ny(handle)); } static int matrix_compare(void *data_interface_a, void *data_interface_b) { struct starpu_matrix_interface *matrix_a = (struct starpu_matrix_interface *) data_interface_a; struct starpu_matrix_interface *matrix_b = (struct starpu_matrix_interface *) data_interface_b; /* Two matricess are considered compatible if they have the same size */ return ((matrix_a->nx == matrix_b->nx) && (matrix_a->ny == matrix_b->ny) && (matrix_a->elemsize == matrix_b->elemsize)); } static void display_matrix_interface(starpu_data_handle_t handle, FILE *f) { struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, STARPU_MAIN_RAM); fprintf(f, "%u\t%u\t", matrix_interface->nx, matrix_interface->ny); } static int pack_matrix_handle(starpu_data_handle_t handle, unsigned node, void **ptr, ssize_t *count) { STARPU_ASSERT(starpu_data_test_if_allocated_on_node(handle, node)); struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, node); *count = matrix_interface->nx*matrix_interface->ny*matrix_interface->elemsize; if (ptr != NULL) { uint32_t y; char *matrix = (void *)matrix_interface->ptr; *ptr = malloc(*count); char *cur = *ptr; for(y=0 ; yny ; y++) { memcpy(cur, matrix, matrix_interface->nx*matrix_interface->elemsize); cur += matrix_interface->nx*matrix_interface->elemsize; matrix += matrix_interface->ld * matrix_interface->elemsize; } } return 0; } static int unpack_matrix_handle(starpu_data_handle_t handle, unsigned node, void *ptr, size_t count) { STARPU_ASSERT(starpu_data_test_if_allocated_on_node(handle, node)); struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, node); STARPU_ASSERT(count == matrix_interface->elemsize * matrix_interface->nx * matrix_interface->ny); uint32_t y; char *cur = ptr; char *matrix = (void *)matrix_interface->ptr; for(y=0 ; yny ; y++) { memcpy(matrix, cur, matrix_interface->nx*matrix_interface->elemsize); cur += matrix_interface->nx*matrix_interface->elemsize; matrix += matrix_interface->ld * matrix_interface->elemsize; } return 0; } static size_t matrix_interface_get_size(starpu_data_handle_t handle) { struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, STARPU_MAIN_RAM); size_t size; size = (size_t)matrix_interface->nx*matrix_interface->ny*matrix_interface->elemsize; return size; } /* offer an access to the data parameters */ uint32_t starpu_matrix_get_nx(starpu_data_handle_t handle) { struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, STARPU_MAIN_RAM); return matrix_interface->nx; } uint32_t starpu_matrix_get_ny(starpu_data_handle_t handle) { struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, STARPU_MAIN_RAM); return matrix_interface->ny; } uint32_t starpu_matrix_get_local_ld(starpu_data_handle_t handle) { unsigned node; node = _starpu_memory_node_get_local_key(); STARPU_ASSERT(starpu_data_test_if_allocated_on_node(handle, node)); struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, node); return matrix_interface->ld; } uintptr_t starpu_matrix_get_local_ptr(starpu_data_handle_t handle) { unsigned node; node = _starpu_memory_node_get_local_key(); STARPU_ASSERT(starpu_data_test_if_allocated_on_node(handle, node)); struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, node); return matrix_interface->ptr; } size_t starpu_matrix_get_elemsize(starpu_data_handle_t handle) { struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) starpu_data_get_interface_on_node(handle, STARPU_MAIN_RAM); return matrix_interface->elemsize; } /* memory allocation/deallocation primitives for the matrix interface */ /* returns the size of the allocated area */ static starpu_ssize_t allocate_matrix_buffer_on_node(void *data_interface_, unsigned dst_node) { uintptr_t addr = 0, handle; struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) data_interface_; uint32_t nx = matrix_interface->nx; uint32_t ny = matrix_interface->ny; uint32_t ld = nx; // by default size_t elemsize = matrix_interface->elemsize; starpu_ssize_t allocated_memory; handle = starpu_malloc_on_node(dst_node, nx*ny*elemsize); if (!handle) return -ENOMEM; if (starpu_node_get_kind(dst_node) != STARPU_OPENCL_RAM) addr = handle; allocated_memory = (size_t)nx*ny*elemsize; /* update the data properly in consequence */ matrix_interface->ptr = addr; matrix_interface->dev_handle = handle; matrix_interface->offset = 0; matrix_interface->ld = ld; return allocated_memory; } static void free_matrix_buffer_on_node(void *data_interface, unsigned node) { struct starpu_matrix_interface *matrix_interface = (struct starpu_matrix_interface *) data_interface; uint32_t nx = matrix_interface->nx; uint32_t ny = matrix_interface->ny; size_t elemsize = matrix_interface->elemsize; starpu_free_on_node(node, matrix_interface->dev_handle, nx*ny*elemsize); } #ifdef STARPU_USE_CUDA static int copy_cuda_common(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, enum cudaMemcpyKind kind, int is_async, cudaStream_t stream) { struct starpu_matrix_interface *src_matrix = src_interface; struct starpu_matrix_interface *dst_matrix = dst_interface; size_t elemsize = src_matrix->elemsize; cudaError_t cures; if (is_async) { _STARPU_TRACE_START_DRIVER_COPY_ASYNC(src_node, dst_node); cures = cudaMemcpy2DAsync((char *)dst_matrix->ptr, dst_matrix->ld*elemsize, (char *)src_matrix->ptr, src_matrix->ld*elemsize, src_matrix->nx*elemsize, src_matrix->ny, kind, stream); _STARPU_TRACE_END_DRIVER_COPY_ASYNC(src_node, dst_node); if (!cures) return -EAGAIN; } cures = cudaMemcpy2D((char *)dst_matrix->ptr, dst_matrix->ld*elemsize, (char *)src_matrix->ptr, src_matrix->ld*elemsize, src_matrix->nx*elemsize, src_matrix->ny, kind); if (STARPU_UNLIKELY(cures)) { int ret = copy_any_to_any(src_interface, src_node, dst_interface, dst_node, (void*)(uintptr_t)is_async); if (ret == -EAGAIN) return ret; if (ret) STARPU_CUDA_REPORT_ERROR(cures); } _STARPU_TRACE_DATA_COPY(src_node, dst_node, (size_t)src_matrix->nx*src_matrix->ny*src_matrix->elemsize); return 0; } static int copy_cuda_peer(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, int is_async, cudaStream_t stream) { #ifdef HAVE_CUDA_MEMCPY_PEER struct starpu_matrix_interface *src_matrix = src_interface; struct starpu_matrix_interface *dst_matrix = dst_interface; size_t elemsize = src_matrix->elemsize; cudaError_t cures; int src_dev = _starpu_memory_node_get_devid(src_node); int dst_dev = _starpu_memory_node_get_devid(dst_node); struct cudaMemcpy3DPeerParms p; memset(&p, 0, sizeof(p)); p.srcDevice = src_dev; p.dstDevice = dst_dev; p.srcPtr = make_cudaPitchedPtr((char *)src_matrix->ptr, src_matrix->ld * elemsize, src_matrix->nx, src_matrix->ny); p.dstPtr = make_cudaPitchedPtr((char *)dst_matrix->ptr, dst_matrix->ld * elemsize, dst_matrix->nx, dst_matrix->ny); p.extent = make_cudaExtent(src_matrix->nx * elemsize, src_matrix->ny, 1); if (is_async) { _STARPU_TRACE_START_DRIVER_COPY_ASYNC(src_node, dst_node); cures = cudaMemcpy3DPeerAsync(&p, stream); _STARPU_TRACE_END_DRIVER_COPY_ASYNC(src_node, dst_node); if (!cures) return -EAGAIN; } cures = cudaMemcpy3DPeer(&p); if (STARPU_UNLIKELY(cures)) STARPU_CUDA_REPORT_ERROR(cures); _STARPU_TRACE_DATA_COPY(src_node, dst_node, (size_t)src_matrix->nx*src_matrix->ny*src_matrix->elemsize); return 0; #else STARPU_ABORT_MSG("CUDA memcpy peer not available, but core triggered one ?!"); #endif } static int copy_cuda_to_ram(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED) { return copy_cuda_common(src_interface, src_node, dst_interface, dst_node, cudaMemcpyDeviceToHost, 0, 0); } static int copy_ram_to_cuda(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED) { return copy_cuda_common(src_interface, src_node, dst_interface, dst_node, cudaMemcpyHostToDevice, 0, 0); } static int copy_cuda_to_cuda(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED) { if (src_node == dst_node) return copy_cuda_common(src_interface, src_node, dst_interface, dst_node, cudaMemcpyDeviceToDevice, 0, 0); else return copy_cuda_peer(src_interface, src_node, dst_interface, dst_node, 0, 0); } static int copy_cuda_to_ram_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cudaStream_t stream) { return copy_cuda_common(src_interface, src_node, dst_interface, dst_node, cudaMemcpyDeviceToHost, 1, stream); } static int copy_ram_to_cuda_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cudaStream_t stream) { return copy_cuda_common(src_interface, src_node, dst_interface, dst_node, cudaMemcpyHostToDevice, 1, stream); } static int copy_cuda_to_cuda_async(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED, cudaStream_t stream) { if (src_node == dst_node) return copy_cuda_common(src_interface, src_node, dst_interface, dst_node, cudaMemcpyDeviceToDevice, 1, stream); else return copy_cuda_peer(src_interface, src_node, dst_interface, dst_node, 1, stream); } #endif // STARPU_USE_CUDA #ifdef STARPU_USE_OPENCL static int copy_opencl_common(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cl_event *event) { struct starpu_matrix_interface *src_matrix = src_interface; struct starpu_matrix_interface *dst_matrix = dst_interface; int ret; STARPU_ASSERT_MSG((src_matrix->ld == src_matrix->nx) && (dst_matrix->ld == dst_matrix->nx), "XXX non contiguous buffers are not properly supported in OpenCL yet. (TODO)"); ret = starpu_opencl_copy_async_sync(src_matrix->dev_handle, src_matrix->offset, src_node, dst_matrix->dev_handle, dst_matrix->offset, dst_node, src_matrix->nx*src_matrix->ny*src_matrix->elemsize, event); _STARPU_TRACE_DATA_COPY(src_node, dst_node, src_matrix->nx*src_matrix->ny*src_matrix->elemsize); return ret; } static int copy_ram_to_opencl_async(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cl_event *event) { return copy_opencl_common(src_interface, src_node, dst_interface, dst_node, event); } static int copy_opencl_to_ram_async(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cl_event *event) { return copy_opencl_common(src_interface, src_node, dst_interface, dst_node, event); } static int copy_opencl_to_opencl_async(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, cl_event *event) { return copy_opencl_common(src_interface, src_node, dst_interface, dst_node, event); } static int copy_ram_to_opencl(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED) { return copy_ram_to_opencl_async(src_interface, src_node, dst_interface, dst_node, NULL); } static int copy_opencl_to_ram(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED) { return copy_opencl_to_ram_async(src_interface, src_node, dst_interface, dst_node, NULL); } static int copy_opencl_to_opencl(void *src_interface, unsigned src_node STARPU_ATTRIBUTE_UNUSED, void *dst_interface, unsigned dst_node STARPU_ATTRIBUTE_UNUSED) { return copy_opencl_to_opencl_async(src_interface, src_node, dst_interface, dst_node, NULL); } #endif static int copy_any_to_any(void *src_interface, unsigned src_node, void *dst_interface, unsigned dst_node, void *async_data) { struct starpu_matrix_interface *src_matrix = (struct starpu_matrix_interface *) src_interface; struct starpu_matrix_interface *dst_matrix = (struct starpu_matrix_interface *) dst_interface; int ret = 0; unsigned y; uint32_t nx = dst_matrix->nx; uint32_t ny = dst_matrix->ny; size_t elemsize = dst_matrix->elemsize; uint32_t ld_src = src_matrix->ld; uint32_t ld_dst = dst_matrix->ld; if (ld_src == nx && ld_dst == nx) { /* Optimize unpartitioned and y-partitioned cases */ if (starpu_interface_copy(src_matrix->dev_handle, src_matrix->offset, src_node, dst_matrix->dev_handle, dst_matrix->offset, dst_node, nx*ny*elemsize, async_data)) ret = -EAGAIN; } else { for (y = 0; y < ny; y++) { uint32_t src_offset = y*ld_src*elemsize; uint32_t dst_offset = y*ld_dst*elemsize; if (starpu_interface_copy(src_matrix->dev_handle, src_matrix->offset + src_offset, src_node, dst_matrix->dev_handle, dst_matrix->offset + dst_offset, dst_node, nx*elemsize, async_data)) ret = -EAGAIN; } } _STARPU_TRACE_DATA_COPY(src_node, dst_node, (size_t)nx*ny*elemsize); return ret; } static ssize_t describe(void *data_interface, char *buf, size_t size) { struct starpu_matrix_interface *matrix = (struct starpu_matrix_interface *) data_interface; return snprintf(buf, size, "M%ux%ux%u", (unsigned) matrix->nx, (unsigned) matrix->ny, (unsigned) matrix->elemsize); }