Use GPU flag

binding.h

@@ -144,3 +144,7 @@ void disable_wal(char *db_path);
 bool has_cuda(void);
 
 bool has_metal(void);
+
+bool has_gpu(void);
+
+void use_gpu(bool v);

src/api/dart_ffi.rs

@@ -671,3 +671,13 @@ pub unsafe extern "C" fn has_cuda() -> bool {
 pub unsafe extern "C" fn has_metal() -> bool {
     crate::has_metal()
 }
+
+#[no_mangle]
+pub unsafe extern "C" fn has_gpu() -> bool {
+    crate::has_gpu()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn use_gpu(v: bool) {
+    crate::use_gpu(v)
+}

src/chain.rs

@@ -34,7 +34,7 @@ use zcash_primitives::zip32::ExtendedFullViewingKey;
 use crate::gpu::cuda::{CudaProcessor, CUDA_CONTEXT};
 #[cfg(feature = "apple_metal")]
 use crate::gpu::metal::MetalProcessor;
-use crate::gpu::trial_decrypt;
+use crate::gpu::{trial_decrypt, USE_GPU};
 
 pub static DOWNLOADED_BYTES: AtomicUsize = AtomicUsize::new(0);
 pub static TRIAL_DECRYPTIONS: AtomicUsize = AtomicUsize::new(0);
@@ -417,14 +417,20 @@ impl DecryptNode {
         network: &Network,
         blocks: Vec<CompactBlock>,
     ) -> Vec<DecryptedBlock> {
-        #[cfg(feature = "cuda")]
-        return self.cuda_decrypt_blocks(network, blocks);
+        let use_gpu = USE_GPU.load(Ordering::Acquire);
+        log::info!("use gpu = {}", use_gpu);
+        if use_gpu {
+            #[cfg(feature = "cuda")]
+            return self.cuda_decrypt_blocks(network, blocks);
 
-        #[cfg(feature = "apple_metal")]
-        return self.metal_decrypt_blocks(network, blocks);
+            #[cfg(feature = "apple_metal")]
+            return self.metal_decrypt_blocks(network, blocks);
 
-        #[allow(unreachable_code)]
-        self.decrypt_blocks_soft(network, blocks)
+            #[allow(unreachable_code)]
+            self.decrypt_blocks_soft(network, blocks)
+        } else {
+            self.decrypt_blocks_soft(network, blocks)
+        }
     }
 
     pub fn decrypt_blocks_soft(

src/gpu.rs

@@ -2,12 +2,41 @@ use crate::chain::{DecryptedBlock, DecryptedNote, Nf};
 use crate::db::AccountViewKey;
 use crate::CompactBlock;
 use anyhow::Result;
+use lazy_static::lazy_static;
+use std::sync::atomic::{AtomicBool, Ordering};
 use zcash_note_encryption::Domain;
 use zcash_primitives::consensus::{BlockHeight, Network};
 use zcash_primitives::sapling::note_encryption::SaplingDomain;
 use zcash_primitives::sapling::SaplingIvk;
 use zcash_primitives::zip32::ExtendedFullViewingKey;
 
+lazy_static! {
+    pub static ref USE_GPU: AtomicBool = AtomicBool::new(true);
+}
+
+#[cfg(feature = "cuda")]
+pub fn has_cuda() -> bool {
+    let cuda = cuda::CUDA_CONTEXT.lock().unwrap();
+    return cuda.is_some();
+}
+
+#[cfg(not(feature = "cuda"))]
+pub fn has_cuda() -> bool {
+    false
+}
+
+pub fn has_metal() -> bool {
+    cfg!(feature = "apple_metal")
+}
+
+pub fn has_gpu() -> bool {
+    cfg!(any(feature = "cuda", feature = "apple_metal"))
+}
+
+pub fn use_gpu(v: bool) {
+    USE_GPU.store(v, Ordering::Release);
+}
+
 #[cfg(feature = "cuda")]
 pub mod cuda;
 

src/lib.rs

@@ -3,6 +3,7 @@
 #[path = "generated/cash.z.wallet.sdk.rpc.rs"]
 pub mod lw_rpc;
 
+use std::sync::atomic::Ordering;
 pub use zcash_params::coin::{get_branch, get_coin_type, CoinType};
 
 // Mainnet
@@ -98,17 +99,4 @@ pub mod nodejs;
 
 mod gpu;
 
-#[cfg(feature = "cuda")]
-pub fn has_cuda() -> bool {
-    let cuda = gpu::cuda::CUDA_CONTEXT.lock().unwrap();
-    return cuda.is_some();
-}
-
-#[cfg(not(feature = "cuda"))]
-pub fn has_cuda() -> bool {
-    false
-}
-
-pub fn has_metal() -> bool {
-    cfg!(feature = "apple_metal")
-}
+pub use gpu::{has_cuda, has_gpu, has_metal, use_gpu};