3067b89ab6
The tests currently have a single writer thread updating the system DSCR with a 1/1000 chance looped only 100 times. So only around one in 10 runs actually do anything. * Add multiple threads to the dscr_explicit_random_test case. * Use a barrier to make all the threads start work as simultaneously as possible. * Use a rwlock and make all threads have a reasonable chance to write to the DSCR on each iteration. PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP is used to prevent writers from starving while all the other threads keep reading. Logging the reads/writes shows a decent mix across the whole test. * Allow all threads a chance to write. * Make the chance of writing more likely. Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230406043320.125138-6-bgray@linux.ibm.com
89 lines
1.8 KiB
C
89 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* POWER Data Stream Control Register (DSCR)
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*
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* This header file contains helper functions and macros
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* required for all the DSCR related test cases.
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*
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* Copyright 2012, Anton Blanchard, IBM Corporation.
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* Copyright 2015, Anshuman Khandual, IBM Corporation.
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*/
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#ifndef _SELFTESTS_POWERPC_DSCR_DSCR_H
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#define _SELFTESTS_POWERPC_DSCR_DSCR_H
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <pthread.h>
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#include <sched.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include "reg.h"
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#include "utils.h"
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#define THREADS 100 /* Max threads */
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#define COUNT 100 /* Max iterations */
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#define DSCR_MAX 16 /* Max DSCR value */
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#define LEN_MAX 100 /* Max name length */
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#define DSCR_DEFAULT "/sys/devices/system/cpu/dscr_default"
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#define CPU_PATH "/sys/devices/system/cpu/"
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#define rmb() asm volatile("lwsync":::"memory")
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#define wmb() asm volatile("lwsync":::"memory")
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#define READ_ONCE(x) (*(volatile typeof(x) *)&(x))
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/* Prilvilege state DSCR access */
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inline unsigned long get_dscr(void)
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{
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return mfspr(SPRN_DSCR_PRIV);
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}
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inline void set_dscr(unsigned long val)
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{
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mtspr(SPRN_DSCR_PRIV, val);
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}
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/* Problem state DSCR access */
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inline unsigned long get_dscr_usr(void)
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{
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return mfspr(SPRN_DSCR);
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}
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inline void set_dscr_usr(unsigned long val)
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{
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mtspr(SPRN_DSCR, val);
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}
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/* Default DSCR access */
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unsigned long get_default_dscr(void)
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{
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int err;
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unsigned long val;
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err = read_ulong(DSCR_DEFAULT, &val, 16);
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if (err) {
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perror("read() failed");
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exit(1);
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}
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return val;
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}
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void set_default_dscr(unsigned long val)
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{
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int err;
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err = write_ulong(DSCR_DEFAULT, val, 16);
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if (err) {
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perror("write() failed");
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exit(1);
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}
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}
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#endif /* _SELFTESTS_POWERPC_DSCR_DSCR_H */
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