c14a9d0a79
This test case is extremely slow, taking around a minute compared to most of the other DSCR tests taking a second at most. Perf shows most time is spent by the kernel switching to each CPU it reads in /sys/devices/system/cpu. This switching is an unavoidable consequnce of reading all the .../cpuN/dscr values. Remove the outer iteration loop from this test case, reducing the reads from 1600 to 16. This still updates the DSCR 16 times and verifies on every CPU each time, so I do not expect the lower coverage to be meaningful. The speedup is significant: back down to ~1 second like the other tests. Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230406043320.125138-7-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) sysfs interface test
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*
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* This test updates to system wide DSCR default through the sysfs interface
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* and then verifies that all the CPU specific DSCR defaults are updated as
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* well verified from their sysfs interfaces.
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*
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* Copyright 2015, Anshuman Khandual, IBM Corporation.
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*/
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#include "dscr.h"
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static int check_cpu_dscr_default(char *file, unsigned long val)
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{
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unsigned long cpu_dscr;
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int err;
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err = read_ulong(file, &cpu_dscr, 16);
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if (err)
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return err;
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if (cpu_dscr != val) {
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printf("DSCR match failed: %ld (system) %ld (cpu)\n",
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val, cpu_dscr);
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return 1;
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}
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return 0;
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}
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static int check_all_cpu_dscr_defaults(unsigned long val)
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{
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DIR *sysfs;
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struct dirent *dp;
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char file[LEN_MAX];
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sysfs = opendir(CPU_PATH);
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if (!sysfs) {
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perror("opendir() failed");
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return 1;
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}
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while ((dp = readdir(sysfs))) {
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int len;
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if (!(dp->d_type & DT_DIR))
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continue;
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if (!strcmp(dp->d_name, "cpuidle"))
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continue;
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if (!strstr(dp->d_name, "cpu"))
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continue;
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len = snprintf(file, LEN_MAX, "%s%s/dscr", CPU_PATH, dp->d_name);
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if (len >= LEN_MAX)
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continue;
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if (access(file, F_OK))
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continue;
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if (check_cpu_dscr_default(file, val)) {
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closedir(sysfs);
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return 1;
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}
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}
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closedir(sysfs);
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return 0;
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}
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int dscr_sysfs(void)
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{
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unsigned long orig_dscr_default;
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SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
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orig_dscr_default = get_default_dscr();
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for (int i = 0; i < DSCR_MAX; i++) {
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set_default_dscr(i);
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if (check_all_cpu_dscr_defaults(i))
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goto fail;
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}
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set_default_dscr(orig_dscr_default);
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return 0;
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fail:
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set_default_dscr(orig_dscr_default);
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return 1;
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}
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int main(int argc, char *argv[])
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{
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return test_harness(dscr_sysfs, "dscr_sysfs_test");
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}
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