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b5906f5f73
Add a selftest for verifying the accuracy of DAMON's access monitoring functionality. The test starts a program of artificial access pattern, monitor the access pattern using DAMON, and check if DAMON finds expected amount of hot data region (working set size) with only acceptable error rate. Note that the acceptable error rate is set with only naive assumptions and small number of tests. Hence failures of the test may not always mean DAMON is broken. Rather than that, those could be a signal to better understand the real accuracy level of DAMON in wider environments. Based on further finding, we could optimize DAMON or adjust the expectation of the test. Link: https://lkml.kernel.org/r/20231212194810.54457-5-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
42 lines
833 B
C
42 lines
833 B
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Artificial memory access program for testing DAMON.
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*/
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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 <time.h>
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int main(int argc, char *argv[])
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{
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char **regions;
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clock_t start_clock;
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int nr_regions;
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int sz_region;
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int access_time_ms;
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int i;
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if (argc != 4) {
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printf("Usage: %s <number> <size (bytes)> <time (ms)>\n",
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argv[0]);
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return -1;
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}
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nr_regions = atoi(argv[1]);
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sz_region = atoi(argv[2]);
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access_time_ms = atoi(argv[3]);
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regions = malloc(sizeof(*regions) * nr_regions);
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for (i = 0; i < nr_regions; i++)
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regions[i] = malloc(sz_region);
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for (i = 0; i < nr_regions; i++) {
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start_clock = clock();
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while ((clock() - start_clock) * 1000 / CLOCKS_PER_SEC <
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access_time_ms)
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memset(regions[i], i, 1024 * 1024 * 10);
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}
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return 0;
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}
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