NAME
spucreate - create a new spu context SYNOPSIS
#include
#include
int spucreate(const char *pathname, int flags, modet mode); int spucreate(const char *pathname, int flags, modet mode, int neighborfd); Note: There is no glibc wrapper for this system call; see NOTES. DESCRIPTION The spucreate() 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 spucreate() 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 spurun(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 spucreate() is closed. The flags argument can be zero or any bitwise OR-ed combination of the following constants: SPUCREATEEVENTSENABLED Rather than using signals for reporting DMA errors, use the event argument to spurun(2). SPUCREATEGANG 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 spucreate(). SPUCREATENOSCHED 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 SPUCREATENOSCHED contexts. Only a subset of the files will be available in this context directory in spufs. Additionally, SPUCREATENOSCHED contexts cannot dump a core file when crashing. Creating SPUCREATENOSCHED contexts requires the CAPSYSNICE capability. SPUCREATEISOLATE 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 SPUCREATEISOLATE contexts also requires the SPUCRE‐ ATENOSCHED flag. SPUCREATEAFFINITYSPU 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 neighborfd argu‐ ment. SPUCREATEAFFINITYMEM 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, spucreate() 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 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 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 SPUCREATENOSCHED flag has been given, but the user does not have the CAPSYSNICE capability. FILES pathname must point to a location beneath the mount point of spufs. By convention, it gets mounted in /spu. VERSIONS The spucreate() 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 spucreate() 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. EXAMPLE See spurun(2) for an example of the use of spucreate() SEE ALSO close(2), spurun(2), capabilities(7), spufs(7) COLOPHON
This page is part of release 3.53 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 2012-08-05 SPUCREATE(2)