<sched.h>: Add sched_getcpu() and cpu_set_t
This adds the cpu_set_t type definition and related functions
and macros used to handle CPU thread affinity.
sched_getcpu()
sched_setaffinity()
sched_getaffinity()
Change-Id: If382ecafde8926341a88478062b275553645065b
diff --git a/libc/include/sched.h b/libc/include/sched.h
index e702470..ca72da7 100644
--- a/libc/include/sched.h
+++ b/libc/include/sched.h
@@ -73,6 +73,162 @@
extern int clone(int (*fn)(void *), void *child_stack, int flags, void* arg, ...);
#endif
+/* Support for cpu thread affinity */
+#ifdef _GNU_SOURCE
+
+extern int sched_getcpu(void);
+
+
+/* Our implementation supports up to 32 independent CPUs, which is also
+ * the maximum supported by the kernel at the moment. GLibc uses 1024 by
+ * default.
+ *
+ * If you want to use more than that, you should use CPU_ALLOC() / CPU_FREE()
+ * and the CPU_XXX_S() macro variants.
+ */
+#define CPU_SETSIZE 32
+
+#define __CPU_BITTYPE unsigned long int /* mandated by the kernel */
+#define __CPU_BITSHIFT 5 /* should be log2(BITTYPE) */
+#define __CPU_BITS (1 << __CPU_BITSHIFT)
+#define __CPU_ELT(x) ((x) >> __CPU_BITSHIFT)
+#define __CPU_MASK(x) ((__CPU_BITTYPE)1 << ((x) & (__CPU_BITS-1)))
+
+typedef struct {
+ __CPU_BITTYPE __bits[ CPU_SETSIZE / __CPU_BITS ];
+} cpu_set_t;
+
+extern int sched_setaffinity(pid_t pid, size_t setsize, const cpu_set_t* set);
+
+extern int sched_getaffinity(pid_t pid, size_t setsize, cpu_set_t* set);
+
+/* Provide optimized implementation for 32-bit cpu_set_t */
+#if CPU_SETSIZE == __CPU_BITS
+
+# define CPU_ZERO(set_) \
+ do{ \
+ (set_)->__bits[0] = 0; \
+ }while(0)
+
+# define CPU_SET(cpu_,set_) \
+ do {\
+ size_t __cpu = (cpu_); \
+ if (__cpu < CPU_SETSIZE) \
+ (set_)->__bits[0] |= __CPU_MASK(__cpu); \
+ }while (0)
+
+# define CPU_CLR(cpu_,set_) \
+ do {\
+ size_t __cpu = (cpu_); \
+ if (__cpu < CPU_SETSIZE) \
+ (set_)->__bits[0] &= ~__CPU_MASK(__cpu); \
+ }while (0)
+
+# define CPU_ISSET(cpu_, set_) \
+ (__extension__({\
+ size_t __cpu = (cpu_); \
+ (cpu_ < CPU_SETSIZE) \
+ ? ((set_)->__bits[0] & __CPU_MASK(__cpu)) != 0 \
+ : 0; \
+ }))
+
+# define CPU_EQUAL(set1_, set2_) \
+ ((set1_)->__bits[0] == (set2_)->__bits[0])
+
+# define __CPU_OP(dst_, set1_, set2_, op_) \
+ do { \
+ (dst_)->__bits[0] = (set1_)->__bits[0] op_ (set2_)->__bits[0]; \
+ } while (0)
+
+# define CPU_COUNT(set_) __builtin_popcountl((set_)->__bits[0])
+
+#else /* CPU_SETSIZE != __CPU_BITS */
+
+# define CPU_ZERO(set_) CPU_ZERO_S(sizeof(cpu_set_t), set_)
+# define CPU_SET(cpu_,set_) CPU_SET_S(cpu_,sizeof(cpu_set_t),set_)
+# define CPU_CLR(cpu_,set_) CPU_CLR_S(cpu_,sizeof(cpu_set_t),set_)
+# define CPU_ISSET(cpu_,set_) CPU_ISSET_S(cpu_,sizeof(cpu_set_t),set_)
+# define CPU_COUNT(set_) CPU_COUNT_S(sizeof(cpu_set_t),set_)
+# define CPU_EQUAL(set1_,set2_) CPU_EQUAL_S(sizeof(cpu_set_t),set1_,set2_)
+
+# define __CPU_OP(dst_,set1_,set2_,op_) __CPU_OP_S(sizeof(cpu_set_t),dst_,set1_,set2_,op_)
+
+#endif /* CPU_SETSIZE != __CPU_BITS */
+
+#define CPU_AND(set1_,set2_) __CPU_OP(set1_,set2_,&)
+#define CPU_OR(set1_,set2_) __CPU_OP(set1_,set2_,|)
+#define CPU_XOR(set1_,set2_) __CPU_OP(set1_,set2_,^)
+
+/* Support for dynamically-allocated cpu_set_t */
+
+#define CPU_ALLOC_SIZE(count) \
+ __CPU_ELT((count) + (__CPU_BITS-1))*sizeof(__CPU_BITTYPE)
+
+#define CPU_ALLOC(count) __sched_cpualloc((count));
+#define CPU_FREE(set) __sched_cpufree((set))
+
+extern cpu_set_t* __sched_cpualloc(size_t count);
+extern void __sched_cpufree(cpu_set_t* set);
+
+#define CPU_ZERO_S(setsize_,set_) \
+ do { \
+ size_t __nn = 0; \
+ size_t __nn_max = (setsize_)/sizeof(__CPU_BITTYPE); \
+ for (; __nn < __nn_max; __nn++) \
+ (set_)->__bits[__nn] = 0; \
+ } while (0)
+
+#define CPU_SET_S(cpu_,setsize_,set_) \
+ do { \
+ size_t __cpu = (cpu_); \
+ if (__cpu < 8*(setsize_)) \
+ (set_)->__bits[__CPU_ELT(__cpu)] |= __CPU_MASK(__cpu); \
+ } while (0)
+
+#define CPU_CLR_S(cpu_,setsize_,set_) \
+ do { \
+ size_t __cpu = (cpu_); \
+ if (__cpu < 8*(setsize_)) \
+ (set_)->__bits[__CPU_ELT(__cpu)] &= ~__CPU_MASK(__cpu); \
+ } while (0)
+
+#define CPU_ISSET_S(cpu_, setsize_, set_) \
+ (__extension__ ({ \
+ size_t __cpu = (cpu_); \
+ (__cpu < 8*(setsize_)) \
+ ? ((set_)->__bits[__CPU_ELT(__cpu)] & __CPU_MASK(__cpu)) != 0 \
+ : 0; \
+ }))
+
+#define CPU_EQUAL_S(setsize_, set1_, set2_) \
+ (__extension__ ({ \
+ __const __CPU_BITTYPE* __src1 = (set1_)->__bits; \
+ __const __CPU_BITTYPE* __src2 = (set2_)->__bits; \
+ size_t __nn = 0, __nn_max = (setsize_)/sizeof(__CPU_BITTYPE); \
+ for (; __nn < __nn_max; __nn++) { \
+ if (__src1[__nn] != __src2[__nn]) \
+ break; \
+ } \
+ __nn == __nn_max; \
+ }))
+
+#define __CPU_OP_S(setsize_, dstset_, srcset1_, srcset2_, op) \
+ do { \
+ cpu_set_t* __dst = (dstset); \
+ const __CPU_BITTYPE* __src1 = (srcset1)->__bits; \
+ const __CPU_BITTYPE* __src2 = (srcset2)->__bits; \
+ size_t __nn = 0, __nn_max = (setsize_)/sizeof(__CPU_BITTYPE); \
+ for (; __nn < __nn_max; __nn++) \
+ (__dst)->__bits[__nn] = __src1[__nn] op __src2[__nn]; \
+ } while (0)
+
+#define CPU_COUNT_S(setsize_, set_) \
+ __sched_cpucount((setsize_), (set_))
+
+extern int __sched_cpucount(size_t setsize, cpu_set_t* set);
+
+#endif /* _GNU_SOURCE */
+
__END_DECLS
#endif /* _SCHED_H_ */