1SPU_CREATE(2) Linux Programmer's Manual SPU_CREATE(2)
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6 spu_create - create a new spu context
7
9 #include <sys/types.h>
10 #include <sys/spu.h>
11 int spu_create(const char *pathname, int flags, mode_t mode);
13 int spu_create(const char *pathname, int flags, mode_t mode,
14 int neighbor_fd);
15 Note: There is no glibc wrapper for this system call; see NOTES.
17
19 The spu_create() system call is used on PowerPC machines that implement
20 the Cell Broadband Engine Architecture in order to access Synergistic
21 Processor Units (SPUs). It creates a new logical context for an SPU in
22 pathname and returns a file descriptor associated with it. pathname
23 must refer to a nonexistent directory in the mount point of the SPU
24 filesystem (spufs). If spu_create() is successful, a directory is cre‐
25 ated at pathname and it is populated with the files described in
26 spufs(7).
27 When a context is created, the returned file descriptor can only be
29 passed to spu_run(2), used as the dirfd argument to the *at family of
30 system calls (e.g., openat(2)), or closed; other operations are not
31 defined. A logical SPU context is destroyed (along with all files cre‐
32 ated within the context's pathname directory) once the last reference
33 to the context has gone; this usually occurs when the file descriptor
34 returned by spu_create() is closed.
35 The flags argument can be zero or any bitwise OR-ed combination of the
37 following constants:
38 SPU_CREATE_EVENTS_ENABLED
40 Rather than using signals for reporting DMA errors, use the
41 event argument to spu_run(2).
42 SPU_CREATE_GANG
44 Create an SPU gang instead of a context. (A gang is a group of
45 SPU contexts that are functionally related to each other and
46 which share common scheduling parameters—priority and policy.
47 In the future, gang scheduling may be implemented causing the
48 group to be switched in and out as a single unit.)
49 A new directory will be created at the location specified by the
51 pathname argument. This gang may be used to hold other SPU con‐
52 texts, by providing a pathname that is within the gang directory
53 to further calls to spu_create().
54 SPU_CREATE_NOSCHED
56 Create a context that is not affected by the SPU scheduler.
57 Once the context is run, it will not be scheduled out until it
58 is destroyed by the creating process.
59 Because the context cannot be removed from the SPU, some func‐
61 tionality is disabled for SPU_CREATE_NOSCHED contexts. Only a
62 subset of the files will be available in this context directory
63 in spufs. Additionally, SPU_CREATE_NOSCHED contexts cannot dump
64 a core file when crashing.
65 Creating SPU_CREATE_NOSCHED contexts requires the CAP_SYS_NICE
67 capability.
68 SPU_CREATE_ISOLATE
70 Create an isolated SPU context. Isolated contexts are protected
71 from some PPE (PowerPC Processing Element) operations, such as
72 access to the SPU local store and the NPC register.
73 Creating SPU_CREATE_ISOLATE contexts also requires the SPU_CRE‐
75 ATE_NOSCHED flag.
76 SPU_CREATE_AFFINITY_SPU
78 Create a context with affinity to another SPU context. This
79 affinity information is used within the SPU scheduling algo‐
80 rithm. Using this flag requires that a file descriptor refer‐
81 ring to the other SPU context be passed in the neighbor_fd argu‐
82 ment.
83 SPU_CREATE_AFFINITY_MEM
85 Create a context with affinity to system memory. This affinity
86 information is used within the SPU scheduling algorithm.
87 The mode argument (minus any bits set in the process's umask(2)) speci‐
89 fies the permissions used for creating the new directory in spufs. See
90 stat(2) for a full list of the possible mode values.
91
93 On success, spu_create() returns a new file descriptor. On error, -1
94 is returned, and errno is set to one of the error codes listed below.
95
97 EACCES The current user does not have write access to the spufs(7)
98 mount point.
99 EEXIST An SPU context already exists at the given pathname.
101 EFAULT pathname is not a valid string pointer in the calling process's
103 address space.
104 EINVAL pathname is not a directory in the spufs(7) mount point, or
106 invalid flags have been provided.
107 ELOOP Too many symbolic links were found while resolving pathname.
109 EMFILE The per-process limit on the number of open file descriptors has
111 been reached.
112 ENAMETOOLONG
114 pathname is too long.
115 ENFILE The system-wide limit on the total number of open files has been
117 reached.
118 ENODEV An isolated context was requested, but the hardware does not
120 support SPU isolation.
121 ENOENT Part of pathname could not be resolved.
123 ENOMEM The kernel could not allocate all resources required.
125 ENOSPC There are not enough SPU resources available to create a new
127 context or the user-specific limit for the number of SPU con‐
128 texts has been reached.
129 ENOSYS The functionality is not provided by the current system, because
131 either the hardware does not provide SPUs or the spufs module is
132 not loaded.
133 ENOTDIR
135 A part of pathname is not a directory.
136 EPERM The SPU_CREATE_NOSCHED flag has been given, but the user does
138 not have the CAP_SYS_NICE capability.
139
141 pathname must point to a location beneath the mount point of spufs. By
142 convention, it gets mounted in /spu.
143
145 The spu_create() system call was added to Linux in kernel 2.6.16.
146
148 This call is Linux-specific and implemented only on the PowerPC archi‐
149 tecture. Programs using this system call are not portable.
150
152 Glibc does not provide a wrapper for this system call; call it using
153 syscall(2). Note however, that spu_create() is meant to be used from
154 libraries that implement a more abstract interface to SPUs, not to be
155 used from regular applications. See ⟨http://www.bsc.es/projects
156 /deepcomputing/linuxoncell/⟩ for the recommended libraries.
157
159 See spu_run(2) for an example of the use of spu_create()
160
162 close(2), spu_run(2), capabilities(7), spufs(7)
163
165 This page is part of release 5.07 of the Linux man-pages project. A
166 description of the project, information about reporting bugs, and the
167 latest version of this page, can be found at
168 https://www.kernel.org/doc/man-pages/.
169Linux 2020-06-09 SPU_CREATE(2)