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SPU_CREATE(2) Linux Programmer's Manual SPU_CREATE(2)
spu_create - create a new spu context
#include <sys/types.h>
#include <sys/spu.h>
int spu_create(const char *pathname, int flags, mode_t mode);
int spu_create(const char *pathname, int flags, mode_t mode,
int neighbor_fd);
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 file system (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 dirfd 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.
The flags argument can be zero or any bitwise OR-ed combination of the
following constants:
SPU_CREATE_EVENTS_ENABLED
Rather than using signals for reporting DMA errors, use the event
argument to spu_run(2).
SPU_CREATE_GANG
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().
SPU_CREATE_NOSCHED
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.
SPU_CREATE_ISOLATE
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.
SPU_CREATE_AFFINITY_SPU
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 neighbor_fd argument.
SPU_CREATE_AFFINITY_MEM
Create a context with affinity to system memory. This affinity
information is used within the SPU scheduling algorithm.
The mode argument (minus any bits set in the process's umask(2)) specifies the
permissions used for creating the new directory in spufs. See stat(2) for a
full list of the possible mode values.
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.
EACCES The current user does not have write access to the spufs(7) mount
point.
EEXIST An SPU context already exists at the given path name.
EFAULT pathname is not a valid string pointer in the calling process's address
space.
EINVAL pathname is not a directory in the spufs(7) mount point, or invalid
flags have been provided.
ELOOP Too many symbolic links were found while resolving pathname.
EMFILE The process has reached its maximum open files limit.
ENAMETOOLONG
pathname is too long.
ENFILE The system has reached the global open files limit.
ENODEV An isolated context was requested, but the hardware does not support
SPU isolation.
ENOENT Part of pathname could not be resolved.
ENOMEM The kernel could not allocate all resources required.
ENOSPC 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.
ENOSYS The functionality is not provided by the current system, because either
the hardware does not provide SPUs or the spufs module is not loaded.
ENOTDIR
A part of pathname is not a directory.
EPERM 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 /spu.
The spu_create() system call was added to Linux in kernel 2.6.16.
This call is Linux-specific and only implemented 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.
See spu_run(2) for an example of the use of spu_create()
close(2), spu_run(2), capabilities(7), spufs(7)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
Linux 2007-12-20 SPU_CREATE(2)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface