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Fix `test_retained` on boxes with a lot of CPUs 

We are trying to create `ncpus * 2` threads for this test and place them
into `VARIABLE_ARRAY`, but `VARIABLE_ARRAY` can not be more than
`VARIABLE_ARRAY_SIZE_MAX` bytes. When there are a lot of threads on the
box test always fails.

```
$ nproc
176

$ make -j`nproc` tests_unit && ./test/unit/retained
<jemalloc>: ../test/unit/retained.c:123: Failed assertion:
"sizeof(thd_t) * (nthreads) <= VARIABLE_ARRAY_SIZE_MAX"
Aborted (core dumped)
```

There is no need for high concurrency for this test as we are only
checking stats there and it's behaviour is quite stable regarding number
of allocating threads.

Limited number of threads to 16 to save compute resources (on CI for
example) and reduce tests running time.

Before the change (`nproc` is 80 on this box).

```
$ make -j`nproc` tests_unit && time ./test/unit/retained
<...>
real    0m0.372s
user    0m14.236s
sys     0m12.338s
```

After the change (same box).

```
$ make -j`nproc` tests_unit && time ./test/unit/retained
<...>
real    0m0.018s
user    0m0.108s
sys     0m0.068s
```
This commit is contained in:
Dmitry Ilvokhin 2024-11-28 07:10:33 -08:00 committed by Qi Wang
parent 6092c980a6
commit 46690c9ec0
1 changed files with 9 additions and 2 deletions
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11
test/unit/retained.c
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@ -110,8 +110,15 @@ TEST_BEGIN(test_retained) {
atomic_store_u(&epoch, 0, ATOMIC_RELAXED);
unsigned nthreads = ncpus * 2;
if (LG_SIZEOF_PTR < 3 && nthreads > 16) {
nthreads = 16; /* 32-bit platform could run out of vaddr. */
if (nthreads > 16) {
/*
* Limit number of threads we are creating for following
* reasons.
* 1. On 32-bit platforms could run out of vaddr.
* 2. On boxes with a lot of CPUs we might have not enough
* memory to fit thd_t into VARIABLE_ARRAY.
*/
nthreads = 16;
}
VARIABLE_ARRAY(thd_t, threads, nthreads);
for (unsigned i = 0; i < nthreads; i++) {