include/hwloc/gl.h

0001 /*
0002  * SPDX-License-Identifier: BSD-3-Clause
0003  * Copyright © 2012 Blue Brain Project, EPFL. All rights reserved.
0004  * Copyright © 2012-2023 Inria.  All rights reserved.
0005  * See COPYING in top-level directory.
0006  */
0007
0008 /** \file
0009  * \brief Macros to help interaction between hwloc and OpenGL displays.
0010  *
0011  * Applications that use both hwloc and OpenGL may want to include
0012  * this file so as to get topology information for OpenGL displays.
0013  */
0014
0015 #ifndef HWLOC_GL_H
0016 #define HWLOC_GL_H
0017
0018 #include "hwloc.h"
0019
0020 #include <stdio.h>
0021 #include <string.h>
0022
0023
0024 #ifdef __cplusplus
0025 extern "C" {
0026 #endif
0027
0028
0029 /** \defgroup hwlocality_gl Interoperability with OpenGL displays
0030  *
0031  * This interface offers ways to retrieve topology information about
0032  * OpenGL displays.
0033  *
0034  * Only the NVIDIA display locality information is currently available,
0035  * using the NV-CONTROL X11 extension and the NVCtrl library.
0036  *
0037  * @{
0038  */
0039
0040 /** \brief Get the hwloc OS device object corresponding to the
0041  * OpenGL display given by port and device index.
0042  *
0043  * \return The hwloc OS device object describing the OpenGL display
0044  * whose port (server) is \p port and device (screen) is \p device.
0045  * \return \c NULL if none could be found.
0046  *
0047  * The topology \p topology does not necessarily have to match the current
0048  * machine. For instance the topology may be an XML import of a remote host.
0049  * I/O devices detection and the GL component must be enabled in the topology.
0050  *
0051  * \note The corresponding PCI device object can be obtained by looking
0052  * at the OS device parent object (unless PCI devices are filtered out).
0053  */
0054 static __hwloc_inline hwloc_obj_t
0055 hwloc_gl_get_display_osdev_by_port_device(hwloc_topology_t topology,
0056                       unsigned port, unsigned device)
0057 {
0058         unsigned x = (unsigned) -1, y = (unsigned) -1;
0059         hwloc_obj_t osdev = NULL;
0060         while ((osdev = hwloc_get_next_osdev(topology, osdev)) != NULL) {
0061                 if (HWLOC_OBJ_OSDEV_GPU == osdev->attr->osdev.type
0062                     && osdev->name
0063                     && sscanf(osdev->name, ":%u.%u", &x, &y) == 2
0064                     && port == x && device == y)
0065                         return osdev;
0066         }
0067     errno = EINVAL;
0068         return NULL;
0069 }
0070
0071 /** \brief Get the hwloc OS device object corresponding to the
0072  * OpenGL display given by name.
0073  *
0074  * \return The hwloc OS device object describing the OpenGL display
0075  * whose name is \p name, built as ":port.device" such as ":0.0" .
0076  * \return \c NULL if none could be found.
0077  *
0078  * The topology \p topology does not necessarily have to match the current
0079  * machine. For instance the topology may be an XML import of a remote host.
0080  * I/O devices detection and the GL component must be enabled in the topology.
0081  *
0082  * \note The corresponding PCI device object can be obtained by looking
0083  * at the OS device parent object (unless PCI devices are filtered out).
0084  */
0085 static __hwloc_inline hwloc_obj_t
0086 hwloc_gl_get_display_osdev_by_name(hwloc_topology_t topology,
0087                    const char *name)
0088 {
0089         hwloc_obj_t osdev = NULL;
0090         while ((osdev = hwloc_get_next_osdev(topology, osdev)) != NULL) {
0091                 if (HWLOC_OBJ_OSDEV_GPU == osdev->attr->osdev.type
0092                     && osdev->name
0093                     && !strcmp(name, osdev->name))
0094                         return osdev;
0095         }
0096     errno = EINVAL;
0097         return NULL;
0098 }
0099
0100 /** \brief Get the OpenGL display port and device corresponding
0101  * to the given hwloc OS object.
0102  *
0103  * Retrieves the OpenGL display port (server) in \p port and device (screen)
0104  * in \p screen that correspond to the given hwloc OS device object.
0105  *
0106  * \return 0 on success.
0107  * \return -1 if none could be found.
0108  *
0109  * The topology \p topology does not necessarily have to match the current
0110  * machine. For instance the topology may be an XML import of a remote host.
0111  * I/O devices detection and the GL component must be enabled in the topology.
0112  */
0113 static __hwloc_inline int
0114 hwloc_gl_get_display_by_osdev(hwloc_topology_t topology __hwloc_attribute_unused,
0115                   hwloc_obj_t osdev,
0116                   unsigned *port, unsigned *device)
0117 {
0118     unsigned x = -1, y = -1;
0119     if (HWLOC_OBJ_OSDEV_GPU == osdev->attr->osdev.type
0120         && sscanf(osdev->name, ":%u.%u", &x, &y) == 2) {
0121         *port = x;
0122         *device = y;
0123         return 0;
0124     }
0125     errno = EINVAL;
0126     return -1;
0127 }
0128
0129 /** @} */
0130
0131
0132 #ifdef __cplusplus
0133 } /* extern "C" */
0134 #endif
0135
0136
0137 #endif /* HWLOC_GL_H */
0138