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Message-ID: <54B5384F.9010805@osg.samsung.com>
Date: Tue, 13 Jan 2015 08:22:55 -0700
From: Shuah Khan <shuahkh@....samsung.com>
To: Anshuman Khandual <khandual@...ux.vnet.ibm.com>,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
CC: mpe@...erman.id.au, benh@...nel.crashing.org, anton@...ba.org,
mikey@...ling.org
Subject: Re: [PATCH V2 06/12] selftests, powerpc: Add test for system wide
DSCR default
On 01/13/2015 03:22 AM, Anshuman Khandual wrote:
> This patch adds a test case for the system wide DSCR default
> value, which when changed through it's sysfs interface must
> be visible to all threads reading DSCR either through the
> privilege state SPR or the problem state SPR. The DSCR value
> change should be immediate as well.
>
> Signed-off-by: Anshuman Khandual <khandual@...ux.vnet.ibm.com>
> ---
> tools/testing/selftests/powerpc/Makefile | 2 +-
> tools/testing/selftests/powerpc/dscr/Makefile | 17 +++
> tools/testing/selftests/powerpc/dscr/dscr.h | 120 ++++++++++++++++++++
> .../selftests/powerpc/dscr/dscr_default_test.c | 121 +++++++++++++++++++++
> 4 files changed, 259 insertions(+), 1 deletion(-)
> create mode 100644 tools/testing/selftests/powerpc/dscr/Makefile
> create mode 100644 tools/testing/selftests/powerpc/dscr/dscr.h
> create mode 100644 tools/testing/selftests/powerpc/dscr/dscr_default_test.c
>
> diff --git a/tools/testing/selftests/powerpc/Makefile b/tools/testing/selftests/powerpc/Makefile
> index f6ff90a..1318883 100644
> --- a/tools/testing/selftests/powerpc/Makefile
> +++ b/tools/testing/selftests/powerpc/Makefile
> @@ -13,7 +13,7 @@ CFLAGS := -Wall -O2 -flto -Wall -Werror -DGIT_VERSION='"$(GIT_VERSION)"' -I$(CUR
>
> export CC CFLAGS
>
> -TARGETS = pmu copyloops mm tm primitives
> +TARGETS = pmu copyloops mm tm primitives dscr
>
> endif
>
> diff --git a/tools/testing/selftests/powerpc/dscr/Makefile b/tools/testing/selftests/powerpc/dscr/Makefile
> new file mode 100644
> index 0000000..0aa90ab
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/dscr/Makefile
> @@ -0,0 +1,17 @@
> +PROGS := dscr_default_test
> +
> +CFLAGS := $(CFLAGS) -lpthread
> +
> +all: $(PROGS)
> +
> +$(PROGS): ../harness.c
> +
> +run_tests: all
> + @-for PROG in $(PROGS); do \
> + ./$$PROG; \
> + done;
> +
> +clean:
> + rm -f $(PROGS) *.o
> +
> +.PHONY: all run_tests clean
> diff --git a/tools/testing/selftests/powerpc/dscr/dscr.h b/tools/testing/selftests/powerpc/dscr/dscr.h
> new file mode 100644
> index 0000000..2e6535b
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/dscr/dscr.h
> @@ -0,0 +1,120 @@
> +/*
> + * POWER Data Stream Control Register (DSCR)
> + *
> + * This header file contains helper functions and macros
> + * required for all the DSCR related test cases.
> + *
> + * Copyright (C) 2012 Anton Blanchard <anton@...ibm.com>, IBM
> + * Copyright (C) 2015 Anshuman Khandual <khandual@...ux.vnet.ibm.com>, IBM
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + */
> +#ifndef _SELFTESTS_POWERPC_DSCR_DSCR_H
> +#define _SELFTESTS_POWERPC_DSCR_DSCR_H
> +
> +#include <unistd.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <fcntl.h>
> +#include <dirent.h>
> +#include <pthread.h>
> +#include <sched.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <sys/wait.h>
> +
> +#include "utils.h"
> +
> +#define SPRN_DSCR 0x11 /* Privilege state SPR */
> +#define SPRN_DSCR_USR 0x03 /* Problem state SPR */
> +#define THREADS 100 /* Max threads */
> +#define COUNT 100 /* Max iterations */
> +#define DSCR_MAX 16 /* Max DSCR value */
> +#define LEN_MAX 100 /* Max name length */
> +
> +#define DSCR_DEFAULT "/sys/devices/system/cpu/dscr_default"
> +#define CPU_PATH "/sys/devices/system/cpu/"
> +
> +#define rmb() asm volatile("lwsync":::"memory")
> +#define wmb() asm volatile("lwsync":::"memory")
> +
> +#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
> +
> +/* Prilvilege state DSCR access */
> +inline unsigned long get_dscr(void)
> +{
> + unsigned long ret;
> +
> + asm volatile("mfspr %0,%1" : "=r" (ret): "i" (SPRN_DSCR));
> +
> + return ret;
> +}
> +
> +inline void set_dscr(unsigned long val)
> +{
> + asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
> +}
> +
> +/* Problem state DSCR access */
> +inline unsigned long get_dscr_usr(void)
> +{
> + unsigned long ret;
> +
> + asm volatile("mfspr %0,%1" : "=r" (ret): "i" (SPRN_DSCR_USR));
> +
> + return ret;
> +}
> +
> +inline void set_dscr_usr(unsigned long val)
> +{
> + asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR_USR));
> +}
> +
> +/* Default DSCR access */
> +unsigned long get_default_dscr(void)
> +{
> + int fd = -1;
> + char buf[16];
> + unsigned long val;
> +
> + if (fd == -1) {
> + fd = open(DSCR_DEFAULT, O_RDONLY);
> + if (fd == -1) {
> + perror("open() failed\n");
> + exit(1);
> + }
> + }
> + memset(buf, 0, sizeof(buf));
> + lseek(fd, 0, SEEK_SET);
> + read(fd, buf, sizeof(buf));
> + sscanf(buf, "%lx", &val);
> + close(fd);
> + return val;
> +}
> +
> +void set_default_dscr(unsigned long val)
> +{
> + int fd = -1;
> + char buf[16];
> +
> + if (fd == -1) {
> + fd = open(DSCR_DEFAULT, O_RDWR);
> + if (fd == -1) {
> + perror("open() failed\n");
> + exit(1);
> + }
> + }
> + sprintf(buf, "%lx\n", val);
> + write(fd, buf, strlen(buf));
> + close(fd);
> +}
> +
> +double uniform_deviate(int seed)
> +{
> + return seed * (1.0 / (RAND_MAX + 1.0));
> +}
> +#endif /* _SELFTESTS_POWERPC_DSCR_DSCR_H */
> diff --git a/tools/testing/selftests/powerpc/dscr/dscr_default_test.c b/tools/testing/selftests/powerpc/dscr/dscr_default_test.c
> new file mode 100644
> index 0000000..fd8b7b9
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/dscr/dscr_default_test.c
> @@ -0,0 +1,121 @@
> +/*
> + * POWER Data Stream Control Register (DSCR) default test
> + *
> + * This test modifies the system wide default DSCR through
> + * it's sysfs interface and then verifies that all threads
> + * see the correct changed DSCR value immediately.
> + *
> + * Copyright (C) 2012 Anton Blanchard <anton@...ibm.com>, IBM
> + * Copyright (C) 2015 Anshuman Khandual <khandual@...ux.vnet.ibm.com>, IBM
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + */
> +#include "dscr.h"
> +
> +static unsigned long dscr; /* System DSCR default */
> +static unsigned long sequence;
> +static unsigned long result[THREADS];
> +
> +static void *do_test(void *in)
> +{
> + unsigned long thread = (unsigned long)in;
> + unsigned long i;
> +
> + for (i = 0; i < COUNT; i++) {
> + unsigned long d, cur_dscr, cur_dscr_usr;
> + unsigned long s1, s2;
> +
> + s1 = ACCESS_ONCE(sequence);
> + if (s1 & 1)
> + continue;
> + rmb();
> +
> + d = dscr;
> + cur_dscr = get_dscr();
> + cur_dscr_usr = get_dscr_usr();
> +
> + rmb();
> + s2 = sequence;
> +
> + if (s1 != s2)
> + continue;
> +
> + if (cur_dscr != d) {
> + fprintf(stderr, "thread %ld kernel DSCR should be %ld "
> + "but is %ld\n", thread, d, cur_dscr);
> + result[thread] = 1;
> + pthread_exit(&result[thread]);
> + }
> +
> + if (cur_dscr_usr != d) {
> + fprintf(stderr, "thread %ld user DSCR should be %ld "
> + "but is %ld\n", thread, d, cur_dscr_usr);
> + result[thread] = 1;
> + pthread_exit(&result[thread]);
> + }
> + }
> + result[thread] = 0;
> + pthread_exit(&result[thread]);
> +}
> +
> +int test_body(void)
> +{
> + pthread_t threads[THREADS];
> + unsigned long i, *status[THREADS];
> +
> + /* Initial DSCR default */
> + dscr = 1;
> + set_default_dscr(dscr);
> +
> + /* Spawn all testing threads */
> + for (i = 0; i < THREADS; i++) {
> + if (pthread_create(&threads[i], NULL, do_test, (void *)i)) {
> + perror("pthread_create() failed\n");
> + exit(1);
> + }
> + }
> +
> + srand(getpid());
> +
> + /* Keep changing the DSCR default */
> + for (i = 0; i < COUNT; i++) {
> + double ret = uniform_deviate(rand());
> +
> + if (ret < 0.0001) {
> + sequence++;
> + wmb();
> +
> + dscr++;
> + if (dscr > DSCR_MAX)
> + dscr = 0;
> +
> + set_default_dscr(dscr);
> +
> + wmb();
> + sequence++;
> + }
> + }
> +
> + /* Individual testing thread exit status */
> + for (i = 0; i < THREADS; i++) {
> + if (pthread_join(threads[i], (void **)&(status[i]))) {
> + perror("pthread_join() failed\n");
> + exit(1);
> + }
> +
> + if (*status[i]) {
> + printf("%ldth thread failed to join with %ld status\n",
> + i, *status[i]);
> + return 1;
> + }
> + }
> + return 0;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + return test_harness(test_body, "dscr_default_test");
> +}
>
Could you please add a .gitignore for powerpc targets as we
discussed earlier. It can be separate patch.
Also, I would like to see the test results reports using
kselftest.h - it can be separate patch in the interest of
getting tests in.
Acked-by: Shuah Khan <shuahkh@....samsung.com>
Please take this through powerpc maintainer git.
thanks,
-- Shuah
--
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@....samsung.com | (970) 217-8978
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