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
17 The spu_create() system call is used on PowerPC machines that implement
18 the Cell Broadband Engine Architecture in order to access Synergistic
19 Processor Units (SPUs). It creates a new logical context for an SPU in
20 pathname and returns a file descriptor associated with it. pathname
21 must refer to a nonexistent directory in the mount point of the SPU
22 file system (spufs). If spu_create() is successful, a directory is
23 created at pathname and it is populated with the files described in
24 spufs(7).
25 When a context is created, the returned file descriptor can only be
27 passed to spu_run(2), used as the dirfd argument to the *at family of
28 system calls (e.g., openat(2)), or closed; other operations are not
29 defined. A logical SPU context is destroyed (along with all files cre‐
30 ated within the context's pathname directory) once the last reference
31 to the context has gone; this usually occurs when the file descriptor
32 returned by spu_create() is closed.
33 The flags argument can be zero or any bitwise OR-ed combination of the
35 following constants:
36 SPU_CREATE_EVENTS_ENABLED
38 Rather than using signals for reporting DMA errors, use the
39 event argument to spu_run(2).
40 SPU_CREATE_GANG
42 Create an SPU gang instead of a context. (A gang is a group of
43 SPU contexts that are functionally related to each other and
44 which share common scheduling parameters — priority and policy.
45 In the future, gang scheduling may be implemented causing the
46 group to be switched in and out as a single unit.)
47 A new directory will be created at the location specified by the
49 pathname argument. This gang may be used to hold other SPU con‐
50 texts, by providing a pathname that is within the gang directory
51 to further calls to spu_create().
52 SPU_CREATE_NOSCHED
54 Create a context that is not affected by the SPU scheduler.
55 Once the context is run, it will not be scheduled out until it
56 is destroyed by the creating process.
57 Because the context cannot be removed from the SPU, some func‐
59 tionality is disabled for SPU_CREATE_NOSCHED contexts. Only a
60 subset of the files will be available in this context directory
61 in spufs. Additionally, SPU_CREATE_NOSCHED contexts cannot dump
62 a core file when crashing.
63 Creating SPU_CREATE_NOSCHED contexts requires the CAP_SYS_NICE
65 capability.
66 SPU_CREATE_ISOLATE
68 Create an isolated SPU context. Isolated contexts are protected
69 from some PPE (PowerPC Processing Element) operations, such as
70 access to the SPU local store and the NPC register.
71 Creating SPU_CREATE_ISOLATE contexts also requires the SPU_CRE‐
73 ATE_NOSCHED flag.
74 SPU_CREATE_AFFINITY_SPU
76 Create a context with affinity to another SPU context. This
77 affinity information is used within the SPU scheduling algo‐
78 rithm. Using this flag requires that a file descriptor refer‐
79 ring to the other SPU context be passed in the neighbor_fd argu‐
80 ment.
81 SPU_CREATE_AFFINITY_MEM
83 Create a context with affinity to system memory. This affinity
84 information is used within the SPU scheduling algorithm.
85 The mode argument (minus any bits set in the process's umask(2)) speci‐
87 fies the permissions used for creating the new directory in spufs. See
88 stat(2) for a full list of the possible mode values.
89
91 On success, spu_create() returns a new file descriptor. On error, -1
92 is returned, and errno is set to one of the error codes listed below.
93
95 EACCES The current user does not have write access to the spufs(7)
96 mount point.
97 EEXIST An SPU context already exists at the given path name.
99 EFAULT pathname is not a valid string pointer in the calling process's
101 address space.
102 EINVAL pathname is not a directory in the spufs(7) mount point, or
104 invalid flags have been provided.
105 ELOOP Too many symbolic links were found while resolving pathname.
107 EMFILE The process has reached its maximum open files limit.
109 ENAMETOOLONG
111 pathname is too long.
112 ENFILE The system has reached the global open files limit.
114 ENODEV An isolated context was requested, but the hardware does not
116 support SPU isolation.
117 ENOENT Part of pathname could not be resolved.
119 ENOMEM The kernel could not allocate all resources required.
121 ENOSPC There are not enough SPU resources available to create a new
123 context or the user-specific limit for the number of SPU con‐
124 texts has been reached.
125 ENOSYS The functionality is not provided by the current system, because
127 either the hardware does not provide SPUs or the spufs module is
128 not loaded.
129 ENOTDIR
131 A part of pathname is not a directory.
132 EPERM The SPU_CREATE_NOSCHED flag has been given, but the user does
134 not have the CAP_SYS_NICE capability.
135
137 pathname must point to a location beneath the mount point of spufs. By
138 convention, it gets mounted in /spu.
139
141 The spu_create() system call was added to Linux in kernel 2.6.16.
142
144 This call is Linux-specific and only implemented on the PowerPC archi‐
145 tecture. Programs using this system call are not portable.
146
148 Glibc does not provide a wrapper for this system call; call it using
149 syscall(2). Note however, that spu_create() is meant to be used from
150 libraries that implement a more abstract interface to SPUs, not to be
151 used from regular applications. See http://www.bsc.es/projects/deep‐
152 computing/linuxoncell/ for the recommended libraries.
153
155 See spu_run(2) for an example of the use of spu_create()
156
158 close(2), spu_run(2), capabilities(7), spufs(7)
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161 This page is part of release 3.25 of the Linux man-pages project. A
162 description of the project, and information about reporting bugs, can
163 be found at http://www.kernel.org/doc/man-pages/.
164Linux 2007-12-20 SPU_CREATE(2)