kernel/linux.git/tools/testing/selftests/powerpc/dscr, branch v6.7

selftests/powerpc/dscr: Restore timeout to DSCR selftests

2023-04-20T03:21:46+00:00

Reducing the time taken by dscr_sysfs_test.c allows restoring the default timeout, which was removed in commit 850507f30c38 ("selftests/powerpc: Turn off timeout setting for benchmarks, dscr, signal, tm") because that test took too long. Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://msgid.link/20230406043320.125138-8-bgray@linux.ibm.com

selftests/powerpc/dscr: Speed up DSCR sysfs tests

2023-04-20T03:21:46+00:00

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 Signed-off-by: Michael Ellerman Link: https://msgid.link/20230406043320.125138-7-bgray@linux.ibm.com

selftests/powerpc/dscr: Improve DSCR explicit random test case

2023-04-20T03:21:45+00:00

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 Signed-off-by: Michael Ellerman Link: https://msgid.link/20230406043320.125138-6-bgray@linux.ibm.com

selftests/powerpc/dscr: Add lockstep test cases to DSCR explicit tests

2023-04-20T03:21:45+00:00

Add new cases to the relevant tests that use explicitly synchronized threads to test the behaviour across context switches with less randomness. By locking the participants to the same CPU we guarantee a context switch occurs each time they make progress, which is a likely failure point if the kernel is not tracking the thread local DSCR correctly. The random case is left in to keep exercising potential edge cases. Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://msgid.link/20230406043320.125138-5-bgray@linux.ibm.com

selftests/powerpc/dscr: Correct typos

2023-04-20T03:21:45+00:00

Correct a couple of typos while working on other improvements to the DSCR tests. Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://msgid.link/20230406043320.125138-2-bgray@linux.ibm.com

selftests/powerpc: Add {read,write}_{long,ulong}

2023-02-09T12:56:45+00:00

Add helper functions to read and write (unsigned) long values directly from/to files. One of the kernel interfaces uses hex strings, so we need to allow passing a base too. Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230203003947.38033-5-bgray@linux.ibm.com

selftests/powerpc: Add generic read/write file util

2023-02-09T12:56:45+00:00

File read/write is reimplemented in about 5 different ways in the various PowerPC selftests. This indicates it should be a common util. Add a common read_file / write_file implementation and convert users to it where (easily) possible. Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230203003947.38033-2-bgray@linux.ibm.com

selftests/powerpc: Fix resource leaks

2022-12-05T10:39:15+00:00

In check_all_cpu_dscr_defaults, opendir() opens the directory stream. Add missing closedir() in the error path to release it. In check_cpu_dscr_default, open() creates an open file descriptor. Add missing close() in the error path to release it. Fixes: ebd5858c904b ("selftests/powerpc: Add test for all DSCR sysfs interfaces") Signed-off-by: Miaoqian Lin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221205084429.570654-1-linmq006@gmail.com

selftests/powerpc: Use mfspr/mtspr macros

2022-12-02T07:04:27+00:00

No need to write inline asm for mtspr/mfspr, we have macros for this in reg.h Signed-off-by: Benjamin Gray Reviewed-by: Andrew Donnellan Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221128041948.58339-2-bgray@linux.ibm.com

selftests/powerpc: Don't run DSCR tests on old systems

2020-09-08T12:24:02+00:00

The DSCR tests fail on systems that don't have DSCR, so check for the DSCR in hwcap and skip if it's not present. Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200819015727.1977134-5-mpe@ellerman.id.au