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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | FILES | VERSIONS | CONFORMING TO | NOTES | EXAMPLE | SEE ALSO | COLOPHON |
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);
Note: There is no glibc wrapper for this system call; see NOTES.
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 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 pathname.
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 per-process limit on the number of open file descriptors
has been reached.
ENAMETOOLONG
pathname is too long.
ENFILE The system-wide limit on the total number of open files has
been reached.
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 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 recom‐
mended 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 4.12 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2015-12-28 SPU_CREATE(2)
Pages that refer to this page: spu_run(2), syscalls(2), spufs(7)