[libc-commits] [libc] [llvm] [libc] GPU RPC interface: add return value to `rpc_host_call` (PR #111288)
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Sun Oct 6 10:06:37 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-offload
Author: Ivan Butygin (Hardcode84)
<details>
<summary>Changes</summary>
---
Full diff: https://github.com/llvm/llvm-project/pull/111288.diff
6 Files Affected:
- (modified) libc/newhdrgen/yaml/gpu/rpc.yaml (+1-1)
- (modified) libc/spec/gpu_ext.td (+1-1)
- (modified) libc/src/gpu/rpc_host_call.cpp (+7-2)
- (modified) libc/src/gpu/rpc_host_call.h (+1-1)
- (modified) libc/utils/gpu/server/rpc_server.cpp (+7-2)
- (modified) offload/test/libc/host_call.c (+15-5)
``````````diff
diff --git a/libc/newhdrgen/yaml/gpu/rpc.yaml b/libc/newhdrgen/yaml/gpu/rpc.yaml
index 61856bc0c7d692..da4f6afb7856d2 100644
--- a/libc/newhdrgen/yaml/gpu/rpc.yaml
+++ b/libc/newhdrgen/yaml/gpu/rpc.yaml
@@ -16,7 +16,7 @@ functions:
- name: rpc_host_call
standards:
- GPUExtensions
- return_type: void
+ return_type: unsigned long long
arguments:
- type: void *
- type: void *
diff --git a/libc/spec/gpu_ext.td b/libc/spec/gpu_ext.td
index dce81ff7786203..d99531dc06bcd6 100644
--- a/libc/spec/gpu_ext.td
+++ b/libc/spec/gpu_ext.td
@@ -7,7 +7,7 @@ def GPUExtensions : StandardSpec<"GPUExtensions"> {
[
FunctionSpec<
"rpc_host_call",
- RetValSpec<VoidType>,
+ RetValSpec<UnsignedLongLongType>,
[ArgSpec<VoidPtr>, ArgSpec<VoidPtr>, ArgSpec<SizeTType>]
>,
]
diff --git a/libc/src/gpu/rpc_host_call.cpp b/libc/src/gpu/rpc_host_call.cpp
index ca2e331340a6cb..f21fadc319c615 100644
--- a/libc/src/gpu/rpc_host_call.cpp
+++ b/libc/src/gpu/rpc_host_call.cpp
@@ -17,14 +17,19 @@ namespace LIBC_NAMESPACE_DECL {
// This calls the associated function pointer on the RPC server with the given
// arguments. We expect that the pointer here is a valid pointer on the server.
-LLVM_LIBC_FUNCTION(void, rpc_host_call, (void *fn, void *data, size_t size)) {
+LLVM_LIBC_FUNCTION(unsigned long long, rpc_host_call,
+ (void *fn, void *data, size_t size)) {
rpc::Client::Port port = rpc::client.open<RPC_HOST_CALL>();
port.send_n(data, size);
port.send([=](rpc::Buffer *buffer) {
buffer->data[0] = reinterpret_cast<uintptr_t>(fn);
});
- port.recv([](rpc::Buffer *) {});
+ unsigned long long ret;
+ port.recv([&](rpc::Buffer *buffer) {
+ ret = static_cast<unsigned long long>(buffer->data[0]);
+ });
port.close();
+ return ret;
}
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/gpu/rpc_host_call.h b/libc/src/gpu/rpc_host_call.h
index 7cfea757ccdfd1..861149dead561e 100644
--- a/libc/src/gpu/rpc_host_call.h
+++ b/libc/src/gpu/rpc_host_call.h
@@ -14,7 +14,7 @@
namespace LIBC_NAMESPACE_DECL {
-void rpc_host_call(void *fn, void *buffer, size_t size);
+unsigned long long rpc_host_call(void *fn, void *buffer, size_t size);
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/utils/gpu/server/rpc_server.cpp b/libc/utils/gpu/server/rpc_server.cpp
index 6951c5ae147df7..ca10e67509ae63 100644
--- a/libc/utils/gpu/server/rpc_server.cpp
+++ b/libc/utils/gpu/server/rpc_server.cpp
@@ -319,13 +319,18 @@ rpc_status_t handle_server_impl(
}
case RPC_HOST_CALL: {
uint64_t sizes[lane_size] = {0};
+ unsigned long long results[lane_size] = {0};
void *args[lane_size] = {nullptr};
port->recv_n(args, sizes,
[&](uint64_t size) { return temp_storage.alloc(size); });
port->recv([&](rpc::Buffer *buffer, uint32_t id) {
- reinterpret_cast<void (*)(void *)>(buffer->data[0])(args[id]);
+ using func_ptr_t = unsigned long long (*)(void *);
+ auto func = reinterpret_cast<func_ptr_t>(buffer->data[0]);
+ results[id] = func(args[id]);
+ });
+ port->send([&](rpc::Buffer *buffer, uint32_t id) {
+ buffer->data[0] = static_cast<uint64_t>(results[id]);
});
- port->send([&](rpc::Buffer *, uint32_t id) {});
break;
}
case RPC_FEOF: {
diff --git a/offload/test/libc/host_call.c b/offload/test/libc/host_call.c
index 11260cc285765d..61c4e14d5b3881 100644
--- a/offload/test/libc/host_call.c
+++ b/offload/test/libc/host_call.c
@@ -8,14 +8,14 @@
#pragma omp begin declare variant match(device = {kind(gpu)})
// Extension provided by the 'libc' project.
-void rpc_host_call(void *fn, void *args, size_t size);
+unsigned long long rpc_host_call(void *fn, void *args, size_t size);
#pragma omp declare target to(rpc_host_call) device_type(nohost)
#pragma omp end declare variant
#pragma omp begin declare variant match(device = {kind(cpu)})
// Dummy host implementation to make this work for all targets.
-void rpc_host_call(void *fn, void *args, size_t size) {
- ((void (*)(void *))fn)(args);
+unsigned long long rpc_host_call(void *fn, void *args, size_t size) {
+ return ((unsigned long long (*)(void *))fn)(args);
}
#pragma omp end declare variant
@@ -25,17 +25,26 @@ typedef struct args_s {
} args_t;
// CHECK-DAG: Thread: 0, Block: 0
+// CHECK-DAG: Result: 42
// CHECK-DAG: Thread: 1, Block: 0
+// CHECK-DAG: Result: 42
// CHECK-DAG: Thread: 0, Block: 1
+// CHECK-DAG: Result: 42
// CHECK-DAG: Thread: 1, Block: 1
+// CHECK-DAG: Result: 42
// CHECK-DAG: Thread: 0, Block: 2
+// CHECK-DAG: Result: 42
// CHECK-DAG: Thread: 1, Block: 2
+// CHECK-DAG: Result: 42
// CHECK-DAG: Thread: 0, Block: 3
+// CHECK-DAG: Result: 42
// CHECK-DAG: Thread: 1, Block: 3
-void foo(void *data) {
+// CHECK-DAG: Result: 42
+long long foo(void *data) {
assert(omp_is_initial_device() && "Not executing on host?");
args_t *args = (args_t *)data;
printf("Thread: %d, Block: %d\n", args->thread_id, args->block_id);
+ return 42;
}
void *fn_ptr = NULL;
@@ -49,6 +58,7 @@ int main() {
#pragma omp parallel num_threads(2)
{
args_t args = {omp_get_thread_num(), omp_get_team_num()};
- rpc_host_call(fn_ptr, &args, sizeof(args_t));
+ unsigned long long res = rpc_host_call(fn_ptr, &args, sizeof(args_t));
+ printf("Result: %d\n", (int)res);
}
}
``````````
</details>
https://github.com/llvm/llvm-project/pull/111288
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