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| author | Joseph Huber <35342157+jhuber6@users.noreply.github.com> | 2023-10-19 17:01:43 -0400 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-10-19 17:01:43 -0400 |
| commit | 630037ede4cec8870764bed27c1289388ac33097 (patch) | |
| tree | 36ddca7d6c0e42e2aa6f2bba494e8f4f950cfbdb /libc/src/stdlib/rand_util.cpp | |
| parent | a39215768b58bb39716820959cedf82c76648770 (diff) | |
[libc] Partially implement 'rand' for the GPU (#66167)
Summary:
This patch partially implements the `rand` function on the GPU. This is
partial because the GPU currently doesn't support thread local storage
or static initializers. To implement this on the GPU. I use 1/8th of the
local / shared memory quota to treak the shared memory as thread local
storage. This is done by simply allocating enough storage for each
thread in the block and indexing into this based off of the thread id.
The downside to this is that it does not initialize `srand` correctly to
be `1` as the standard says, it is also wasteful. In the future we
should figure out a way to support TLS on the GPU so that this can be
completely common and less resource intensive.
Diffstat (limited to 'libc/src/stdlib/rand_util.cpp')
| -rw-r--r-- | libc/src/stdlib/rand_util.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/libc/src/stdlib/rand_util.cpp b/libc/src/stdlib/rand_util.cpp index fc2cd304e77d..1f3dbce9c786 100644 --- a/libc/src/stdlib/rand_util.cpp +++ b/libc/src/stdlib/rand_util.cpp @@ -11,8 +11,14 @@ namespace LIBC_NAMESPACE { +#ifdef LIBC_TARGET_ARCH_IS_GPU +// FIXME: Local GPU memory cannot be initialized so we cannot currently provide +// a standard compliant default value. +ThreadLocal<unsigned long> rand_next; +#else // C standard 7.10p2: If 'rand' is called before 'srand' it is to proceed as if // the 'srand' function was called with a value of '1'. LIBC_THREAD_LOCAL unsigned long rand_next = 1; +#endif } // namespace LIBC_NAMESPACE |