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man:spu_create

SPU_CREATE(2) Linux Programmer's Manual SPU_CREATE(2)

NAME

     spu_create - create a new spu context

SYNOPSIS

     #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.

DESCRIPTION

     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 cre-
     ated  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 cre-
     ated 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 con-
            texts, 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 func-
            tionality 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_CRE-
            ATE_NOSCHED flag.
     SPU_CREATE_AFFINITY_SPU
            Create  a  context  with  affinity to another SPU context.  This
            affinity information is used within  the  SPU  scheduling  algo-
            rithm.   Using  this flag requires that a file descriptor refer-
            ring to the other SPU context be passed in the neighbor_fd argu-
            ment.
     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)) speci-
     fies the permissions used for creating the new directory in spufs.  See
     stat(2) for a full list of the possible mode values.

RETURN VALUE

     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.

ERRORS

     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  con-
            texts 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.

FILES

     pathname must point to a location beneath the mount point of spufs.  By
     convention, it gets mounted in /spu.

VERSIONS

     The spu_create() system call was added to Linux in kernel 2.6.16.

CONFORMING TO

     This  call is Linux-specific and implemented only on the PowerPC archi-
     tecture.  Programs using this system call are not portable.

NOTES

     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 for the recommended libraries.

EXAMPLE

     See spu_run(2) for an example of the use of spu_create()

SEE ALSO

     close(2), spu_run(2), capabilities(7), spufs(7)

COLOPHON

     This  page  is  part of release 4.16 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 2017-09-15 SPU_CREATE(2)

/data/webs/external/dokuwiki/data/pages/man/spu_create.txt · Last modified: 2019/05/17 09:32 by 127.0.0.1

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