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13684e966d
When running the in-kernel Dhrystone benchmark with
CONFIG_DEBUG_PREEMPT=y:
BUG: using smp_processor_id() in preemptible [00000000] code: bash/938
Fix this by not using smp_processor_id() directly, but instead wrapping
the whole benchmark inside a get_cpu()/put_cpu() pair. This makes sure
the whole benchmark is run on the same CPU core, and the reported values
are consistent.
Link: https://lkml.kernel.org/r/b0d29932bb24ad82cea7f821e295c898e9657be0.1678890070.git.geert+renesas@glider.be
Fixes: d5528cc168 ("lib: add Dhrystone benchmark test")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reported-by: Tobias Klausmann <klausman@schwarzvogel.de>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217179
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
88 lines
1.7 KiB
C
88 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Dhrystone benchmark test module
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*
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* Copyright (C) 2022 Glider bv
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*/
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#include "dhry.h"
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/mutex.h>
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#include <linux/smp.h>
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#define DHRY_VAX 1757
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static int dhry_run_set(const char *val, const struct kernel_param *kp);
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static const struct kernel_param_ops run_ops = {
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.flags = KERNEL_PARAM_OPS_FL_NOARG,
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.set = dhry_run_set,
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};
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static bool dhry_run;
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module_param_cb(run, &run_ops, &dhry_run, 0200);
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MODULE_PARM_DESC(run, "Run the test (default: false)");
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static int iterations = -1;
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module_param(iterations, int, 0644);
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MODULE_PARM_DESC(iterations,
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"Number of iterations through the benchmark (default: auto)");
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static void dhry_benchmark(void)
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{
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unsigned int cpu = get_cpu();
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int i, n;
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if (iterations > 0) {
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n = dhry(iterations);
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goto report;
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}
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for (i = DHRY_VAX; i > 0; i <<= 1) {
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n = dhry(i);
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if (n != -EAGAIN)
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break;
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}
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report:
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put_cpu();
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if (n >= 0)
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pr_info("CPU%u: Dhrystones per Second: %d (%d DMIPS)\n", cpu,
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n, n / DHRY_VAX);
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else if (n == -EAGAIN)
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pr_err("Please increase the number of iterations\n");
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else
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pr_err("Dhrystone benchmark failed error %pe\n", ERR_PTR(n));
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}
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static int dhry_run_set(const char *val, const struct kernel_param *kp)
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{
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int ret;
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if (val) {
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ret = param_set_bool(val, kp);
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if (ret)
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return ret;
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} else {
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dhry_run = true;
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}
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if (dhry_run && system_state == SYSTEM_RUNNING)
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dhry_benchmark();
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return 0;
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}
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static int __init dhry_init(void)
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{
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if (dhry_run)
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dhry_benchmark();
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return 0;
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}
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module_init(dhry_init);
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MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
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MODULE_LICENSE("GPL");
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