spu_create - create a new spu context
The spu_create() system call is used on PowerPC
machines that implement the Cell Broadband Engine Architecture in order
to access Synergistic Processor Units (SPUs). It creates a new logical
context for an SPU in
pathname and returns a file descriptor
associated with it.
pathname must refer to a nonexistent
directory in the mount point of the SPU filesystem
(spufs). If spu_create() is
successful, a directory is created at
pathname and it is
populated with the files described in spufs(7).
When a context is created, the returned file descriptor can only be
passed to spu_run(2), used as the
argument to the *at family of system calls (e.g.,
openat(2)), or closed; other operations are not
defined. A logical SPU context is destroyed (along with all files
created within the context's
pathname directory) once the last
reference to the context has gone; this usually occurs when the file
descriptor returned by spu_create() is closed.
neighbor_fd is used only when the
SPU_CREATE_AFFINITY_SPU flag is specified; see
flags argument can be zero or any bitwise OR-ed
combination of the following constants:
Rather than using signals for reporting DMA errors, use the
event argument to spu_run(2).
Create an SPU gang instead of a context. (A gang is a group of SPU contexts that are functionally related to each other and which share common scheduling parameters—priority and policy. In the future, gang scheduling may be implemented causing the group to be switched in and out as a single unit.)
A new directory will be created at the location specified by the
pathname argument. This gang may be used to hold other SPU
contexts, by providing a pathname that is within the gang directory to
further calls to spu_create().
Create a context that is not affected by the SPU scheduler. Once the context is run, it will not be scheduled out until it is destroyed by the creating process.
Because the context cannot be removed from the SPU, some functionality is disabled for SPU_CREATE_NOSCHED contexts. Only a subset of the files will be available in this context directory in spufs. Additionally, SPU_CREATE_NOSCHED contexts cannot dump a core file when crashing.
Creating SPU_CREATE_NOSCHED contexts requires the CAP_SYS_NICE capability.
Create an isolated SPU context. Isolated contexts are protected from some PPE (PowerPC Processing Element) operations, such as access to the SPU local store and the NPC register.
Creating SPU_CREATE_ISOLATE contexts also requires the SPU_CREATE_NOSCHED flag.
Create a context with affinity to another SPU context. This affinity
information is used within the SPU scheduling algorithm. Using this flag
requires that a file descriptor referring to the other SPU context be
passed in the
Create a context with affinity to system memory. This affinity information is used within the SPU scheduling algorithm.
On success, spu_create() returns a new file
descriptor. On error, -1 is returned, and
errno is set to one
of the error codes listed below.
The current user does not have write access to the spufs(7) mount point.
An SPU context already exists at the given pathname.
pathname is not a valid string pointer in the calling
process's address space.
pathname is not a directory in the spufs(7)
mount point, or invalid flags have been provided.
Too many symbolic links were found while resolving
The per-process limit on the number of open file descriptors has been reached.
pathname is too long.
The system-wide limit on the total number of open files has been reached.
An isolated context was requested, but the hardware does not support SPU isolation.
pathname could not be resolved.
The kernel could not allocate all resources required.
There are not enough SPU resources available to create a new context or the user-specific limit for the number of SPU contexts has been reached.
The functionality is not provided by the current system, because either the hardware does not provide SPUs or the spufs module is not loaded.
A part of
pathname is not a directory.
The SPU_CREATE_NOSCHED flag has been given, but the user does not have the CAP_SYS_NICE capability.
pathname must point to a location beneath the mount point of
spufs. By convention, it gets mounted in
This call is Linux-specific and implemented only on the PowerPC architecture. Programs using this system call are not portable.
Glibc does not provide a wrapper for this system call; call it using syscall(2). Note however, that spu_create() is meant to be used from libraries that implement a more abstract interface to SPUs, not to be used from regular applications. See http://www.bsc.es/projects/deepcomputing/linuxoncell/"> for the recommended libraries.
Prior to the addition of the SPU_CREATE_AFFINITY_SPU
flag in Linux 2.6.23, the spu_create() system call took
only three arguments (i.e., there was no
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