openblas_threads_callback mechanism for changing threads backend

cblas.h

@@ -25,6 +25,11 @@ char* openblas_get_config(void);
 /*Get the CPU corename on runtime.*/
 char* openblas_get_corename(void);
 
+/*Set the threading backend to a custom callback.*/
+typedef void (*openblas_dojob_callback)(int thread_num, void *jobdata, void *dojob_data);
+typedef void (*openblas_threads_callback)(void *callback_data, openblas_dojob_callback dojob, int numjobs, size_t jobdata_elsize, void *jobdata, void *dojob_data);
+void openblas_set_threads_callback(openblas_threads_callback callback, void *callback_data);
+
 /* Get the parallelization type which is used by OpenBLAS */
 int openblas_get_parallel(void);
 /* OpenBLAS is compiled for sequential use  */
@@ -52,7 +57,7 @@ typedef enum CBLAS_UPLO      {CblasUpper=121, CblasLower=122} CBLAS_UPLO;
 typedef enum CBLAS_DIAG      {CblasNonUnit=131, CblasUnit=132} CBLAS_DIAG;
 typedef enum CBLAS_SIDE      {CblasLeft=141, CblasRight=142} CBLAS_SIDE;
 typedef CBLAS_ORDER CBLAS_LAYOUT;
-	
+
 float  cblas_sdsdot(OPENBLAS_CONST blasint n, OPENBLAS_CONST float alpha, OPENBLAS_CONST float *x, OPENBLAS_CONST blasint incx, OPENBLAS_CONST float *y, OPENBLAS_CONST blasint incy);
 double cblas_dsdot (OPENBLAS_CONST blasint n, OPENBLAS_CONST float *x, OPENBLAS_CONST blasint incx, OPENBLAS_CONST float *y, OPENBLAS_CONST blasint incy);
 float  cblas_sdot(OPENBLAS_CONST blasint n, OPENBLAS_CONST float  *x, OPENBLAS_CONST blasint incx, OPENBLAS_CONST float  *y, OPENBLAS_CONST blasint incy);
@@ -350,32 +355,32 @@ void cblas_caxpby(OPENBLAS_CONST blasint n, OPENBLAS_CONST void *alpha, OPENBLAS
 
 void cblas_zaxpby(OPENBLAS_CONST blasint n, OPENBLAS_CONST void *alpha, OPENBLAS_CONST void *x, OPENBLAS_CONST blasint incx,OPENBLAS_CONST void *beta, void *y, OPENBLAS_CONST blasint incy);
 
-void cblas_somatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float calpha, OPENBLAS_CONST float *a, 
-		     OPENBLAS_CONST blasint clda, float *b, OPENBLAS_CONST blasint cldb); 
+void cblas_somatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float calpha, OPENBLAS_CONST float *a,
+		     OPENBLAS_CONST blasint clda, float *b, OPENBLAS_CONST blasint cldb);
 void cblas_domatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double calpha, OPENBLAS_CONST double *a,
-		     OPENBLAS_CONST blasint clda, double *b, OPENBLAS_CONST blasint cldb); 
-void cblas_comatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float* calpha, OPENBLAS_CONST float* a, 
-		     OPENBLAS_CONST blasint clda, float*b, OPENBLAS_CONST blasint cldb); 
-void cblas_zomatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double* calpha, OPENBLAS_CONST double* a, 
-		     OPENBLAS_CONST blasint clda,  double *b, OPENBLAS_CONST blasint cldb); 
-
-void cblas_simatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float calpha, float *a, 
-		     OPENBLAS_CONST blasint clda, OPENBLAS_CONST blasint cldb); 
+		     OPENBLAS_CONST blasint clda, double *b, OPENBLAS_CONST blasint cldb);
+void cblas_comatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float* calpha, OPENBLAS_CONST float* a,
+		     OPENBLAS_CONST blasint clda, float*b, OPENBLAS_CONST blasint cldb);
+void cblas_zomatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double* calpha, OPENBLAS_CONST double* a,
+		     OPENBLAS_CONST blasint clda,  double *b, OPENBLAS_CONST blasint cldb);
+
+void cblas_simatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float calpha, float *a,
+		     OPENBLAS_CONST blasint clda, OPENBLAS_CONST blasint cldb);
 void cblas_dimatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double calpha, double *a,
-		     OPENBLAS_CONST blasint clda, OPENBLAS_CONST blasint cldb); 
-void cblas_cimatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float* calpha, float* a, 
-		     OPENBLAS_CONST blasint clda, OPENBLAS_CONST blasint cldb); 
-void cblas_zimatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double* calpha, double* a, 
-		     OPENBLAS_CONST blasint clda, OPENBLAS_CONST blasint cldb); 
-
-void cblas_sgeadd(OPENBLAS_CONST enum CBLAS_ORDER CORDER,OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float calpha, float *a, OPENBLAS_CONST blasint clda, OPENBLAS_CONST float cbeta, 
-		  float *c, OPENBLAS_CONST blasint cldc); 
-void cblas_dgeadd(OPENBLAS_CONST enum CBLAS_ORDER CORDER,OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double calpha, double *a, OPENBLAS_CONST blasint clda, OPENBLAS_CONST double cbeta, 
-		  double *c, OPENBLAS_CONST blasint cldc); 
-void cblas_cgeadd(OPENBLAS_CONST enum CBLAS_ORDER CORDER,OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float *calpha, float *a, OPENBLAS_CONST blasint clda, OPENBLAS_CONST float *cbeta, 
-		  float *c, OPENBLAS_CONST blasint cldc); 
-void cblas_zgeadd(OPENBLAS_CONST enum CBLAS_ORDER CORDER,OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double *calpha, double *a, OPENBLAS_CONST blasint clda, OPENBLAS_CONST double *cbeta, 
-		  double *c, OPENBLAS_CONST blasint cldc); 
+		     OPENBLAS_CONST blasint clda, OPENBLAS_CONST blasint cldb);
+void cblas_cimatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float* calpha, float* a,
+		     OPENBLAS_CONST blasint clda, OPENBLAS_CONST blasint cldb);
+void cblas_zimatcopy(OPENBLAS_CONST enum CBLAS_ORDER CORDER, OPENBLAS_CONST enum CBLAS_TRANSPOSE CTRANS, OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double* calpha, double* a,
+		     OPENBLAS_CONST blasint clda, OPENBLAS_CONST blasint cldb);
+
+void cblas_sgeadd(OPENBLAS_CONST enum CBLAS_ORDER CORDER,OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float calpha, float *a, OPENBLAS_CONST blasint clda, OPENBLAS_CONST float cbeta,
+		  float *c, OPENBLAS_CONST blasint cldc);
+void cblas_dgeadd(OPENBLAS_CONST enum CBLAS_ORDER CORDER,OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double calpha, double *a, OPENBLAS_CONST blasint clda, OPENBLAS_CONST double cbeta,
+		  double *c, OPENBLAS_CONST blasint cldc);
+void cblas_cgeadd(OPENBLAS_CONST enum CBLAS_ORDER CORDER,OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST float *calpha, float *a, OPENBLAS_CONST blasint clda, OPENBLAS_CONST float *cbeta,
+		  float *c, OPENBLAS_CONST blasint cldc);
+void cblas_zgeadd(OPENBLAS_CONST enum CBLAS_ORDER CORDER,OPENBLAS_CONST blasint crows, OPENBLAS_CONST blasint ccols, OPENBLAS_CONST double *calpha, double *a, OPENBLAS_CONST blasint clda, OPENBLAS_CONST double *cbeta,
+		  double *c, OPENBLAS_CONST blasint cldc);
 
 
 #ifdef __cplusplus

common_interface.h

@@ -47,6 +47,12 @@ int    BLASFUNC(xerbla)(char *, blasint *info, blasint);
 
 void    openblas_set_num_threads_(int *);
 
+typedef void (*openblas_dojob_callback)(int thread_num, void *jobdata, void *dojob_data);
+typedef void (*openblas_threads_callback)(void *callback_data, openblas_dojob_callback dojob, int numjobs, size_t jobdata_elsize, void *jobdata, void *dojob_data);
+void openblas_set_threads_callback(openblas_threads_callback callback, void *callback_data);
+extern openblas_threads_callback openblas_threads_callback_;
+extern void *openblas_threads_callback_data_;
+
 FLOATRET  BLASFUNC(sdot)  (blasint *, float  *, blasint *, float  *, blasint *);
 FLOATRET  BLASFUNC(sdsdot)(blasint *, float  *,        float  *, blasint *, float  *, blasint *);
 
@@ -761,10 +767,10 @@ void    BLASFUNC(dimatcopy) (char *, char *, blasint *, blasint *, double  *, do
 void    BLASFUNC(cimatcopy) (char *, char *, blasint *, blasint *, float  *, float  *, blasint *, blasint *);
 void    BLASFUNC(zimatcopy) (char *, char *, blasint *, blasint *, double  *, double  *, blasint *, blasint *);
 
-void    BLASFUNC(sgeadd) (blasint *, blasint *, float *, float *, blasint *, float *, float *, blasint*); 
-void    BLASFUNC(dgeadd) (blasint *, blasint *, double *, double *, blasint *, double *, double *, blasint*); 
-void    BLASFUNC(cgeadd) (blasint *, blasint *, float *, float *, blasint *, float *, float *, blasint*); 
-void    BLASFUNC(zgeadd) (blasint *, blasint *, double *, double *, blasint *, double *, double *, blasint*); 
+void    BLASFUNC(sgeadd) (blasint *, blasint *, float *, float *, blasint *, float *, float *, blasint*);
+void    BLASFUNC(dgeadd) (blasint *, blasint *, double *, double *, blasint *, double *, double *, blasint*);
+void    BLASFUNC(cgeadd) (blasint *, blasint *, float *, float *, blasint *, float *, float *, blasint*);
+void    BLASFUNC(zgeadd) (blasint *, blasint *, double *, double *, blasint *, double *, double *, blasint*);
 
 
 #ifdef __cplusplus

driver/others/CMakeLists.txt

@@ -39,6 +39,7 @@ set(COMMON_SOURCES
   openblas_env.c
   openblas_get_num_procs.c
   openblas_get_num_threads.c
+  blas_server_callback.c
 )
 
 # these need to have NAME/CNAME set, so use GenerateNamedObjects, but don't use standard name mangling

driver/others/Makefile

@@ -1,7 +1,7 @@
 TOPDIR	= ../..
 include ../../Makefile.system
 
-COMMONOBJS	 = memory.$(SUFFIX) xerbla.$(SUFFIX) c_abs.$(SUFFIX) z_abs.$(SUFFIX) openblas_set_num_threads.$(SUFFIX) openblas_get_num_threads.$(SUFFIX) openblas_get_num_procs.$(SUFFIX) openblas_get_config.$(SUFFIX) openblas_get_parallel.$(SUFFIX) openblas_error_handle.$(SUFFIX) openblas_env.$(SUFFIX)
+COMMONOBJS	 = memory.$(SUFFIX) xerbla.$(SUFFIX) c_abs.$(SUFFIX) z_abs.$(SUFFIX) openblas_set_num_threads.$(SUFFIX) openblas_get_num_threads.$(SUFFIX) openblas_get_num_procs.$(SUFFIX) openblas_get_config.$(SUFFIX) openblas_get_parallel.$(SUFFIX) openblas_error_handle.$(SUFFIX) openblas_env.$(SUFFIX) blas_server_callback.$(SUFFIX)
 
 #COMMONOBJS	+= slamch.$(SUFFIX) slamc3.$(SUFFIX) dlamch.$(SUFFIX)  dlamc3.$(SUFFIX)
 

driver/others/blas_server_callback.c

@@ -0,0 +1,13 @@
+#include "common.h"
+
+/* global variable to change threading backend from openblas-managed to caller-managed */
+openblas_threads_callback openblas_threads_callback_ = 0;
+void *openblas_threads_callback_data_ = 0;
+
+/* non-threadsafe function should be called before any other
+   openblas function to change how threads are managed */
+void openblas_set_threads_callback(openblas_threads_callback callback, void *callback_data)
+{
+  openblas_threads_callback_ = callback;
+  openblas_threads_callback_data_ = callback_data;
+}

driver/others/blas_server_omp.c

@@ -75,7 +75,8 @@ void goto_set_num_threads(int num_threads) {
 
   blas_cpu_number  = num_threads;
 
-  omp_set_num_threads(blas_cpu_number);
+  if (!openblas_threads_callback_)
+    omp_set_num_threads(blas_cpu_number);
 
   //adjust buffer for each thread
   for(i=0; i<MAX_PARALLEL_NUMBER; i++) {
@@ -222,10 +223,9 @@ static void legacy_exec(void *func, int mode, blas_arg_t *args, void *sb){
       }
 }
 
-static void exec_threads(blas_queue_t *queue, int buf_index){
-
+static void exec_threads(int thread_num, blas_queue_t *queue, int *buf_index){
   void *buffer, *sa, *sb;
-  int pos=0, release_flag=0;
+  int release_flag=0;
 
   buffer = NULL;
   sa = queue -> sa;
@@ -238,8 +238,7 @@ static void exec_threads(blas_queue_t *queue, int buf_index){
 
   if ((sa == NULL) && (sb == NULL) && ((queue -> mode & BLAS_PTHREAD) == 0)) {
 
-    pos = omp_get_thread_num();
-    buffer = blas_thread_buffer[buf_index][pos];
+    buffer = blas_thread_buffer[*buf_index][thread_num];
 
     //fallback
     if(buffer==NULL) {
@@ -335,14 +334,25 @@ int exec_blas(BLASLONG num, blas_queue_t *queue){
       break;
   }
 
+  if (openblas_threads_callback_) {
+#ifndef USE_SIMPLE_THREADED_LEVEL3
+    for (i = 0; i < num; i ++)
+      queue[i].position = i;
+#endif
+    openblas_threads_callback_(openblas_threads_callback_data_, (openblas_dojob_callback) exec_threads, num, sizeof(blas_queue_t), (void*) queue, (void*) &buf_index);
+    return;
+  }
+
 #pragma omp parallel for schedule(OMP_SCHED)
+
+#pragma omp parallel for schedule(static)
   for (i = 0; i < num; i ++) {
 
 #ifndef USE_SIMPLE_THREADED_LEVEL3
     queue[i].position = i;
 #endif
 
-    exec_threads(&queue[i], buf_index);
+    exec_threads(omp_get_thread_num(), &queue[i], &buf_index);
   }
 
 #if __STDC_VERSION__ >= 201112L