do not parallelize searching and use smaller buffers

apps/fsearch/fsearch.cpp

@@ -3,7 +3,6 @@
 #include <fcntl.h>
 #include <unistd.h>
 
-#include <array>
 #include <atomic>
 #include <boost/program_options.hpp>
 #include <cstdlib>
@@ -26,7 +25,6 @@
 namespace fs = std::filesystem;
 namespace po = boost::program_options;
 
-#define EMPER_READ_BUFSIZE 65536
 #define EMPER_SEARCH_BUFSIZE 4096
 
 static const char* needle;
@@ -37,17 +35,11 @@ static emper::Semaphore* max_open;
 
 static emper::lib::ShardedFileBuffer* outBuf;
 
-void searchPart(const char* buf, size_t len, std::atomic<bool>* found) {
-	if (found->load(std::memory_order_consume)) return;
-
-	if (memmem(buf, len, needle, needle_len)) found->store(true, std::memory_order_release);
-}
-
 // NOLINTNEXTLINE(clang-diagnostic-unknown-attributes)
 emper_fibril void search(const std::string& path) {
 	emper::io::RegisteredFile file;
 
-	auto* buf = new std::array<char, EMPER_READ_BUFSIZE>;
+	char buf[EMPER_SEARCH_BUFSIZE];
 
 	emper::io::OpenFuture openFuture(file, path.c_str(), O_RDONLY);
 	int res = openFuture.submitAndWait();
@@ -55,7 +47,7 @@ emper_fibril void search(const std::string& path) {
 		DIE_MSG("opening " << path << " failed:" << strerror(-res));
 	}
 
-	emper::io::ReadFuture readFuture(file, buf->data(), buf->size(), 0);
+	emper::io::ReadFuture readFuture(file, buf, sizeof(buf), 0);
 	// readFuture.setDependency(openFuture);
 
 	int bytes_read = readFuture.submitAndWait();
@@ -68,29 +60,12 @@ emper_fibril void search(const std::string& path) {
 	// }
 
 	while (bytes_read > 0) {
-		// Parallel searching
-		std::atomic<bool> found = false;
-		{
-			const size_t parts = bytes_read / EMPER_SEARCH_BUFSIZE + 1;
-
-			Fibril fibril;
-
-			for (size_t i = 0; i < parts; ++i) {
-				const size_t partBegin = i * EMPER_SEARCH_BUFSIZE;
-				const char* partBuf = &(*buf)[partBegin];
-				const size_t partLen = (i < parts - 1) ? EMPER_SEARCH_BUFSIZE : bytes_read - partBegin;
-
-				fibril.spawn(searchPart, partBuf, partLen, &found);
-			}
-			// The fibril is implicitly joined when dropped
-		}
-
-		if (found.load(std::memory_order_acquire)) {
+		if (memmem(buf, bytes_read, needle, needle_len)) {
 			outBuf->getStream() << path << std::endl;
-			goto out;
+			return;
 		}
 
-		emper::io::ReadFuture readFuture(file, buf->data(), buf->size(), -1);
+		emper::io::ReadFuture readFuture(file, buf, sizeof(buf), -1);
 		bytes_read = readFuture.submitAndWait();
 	}
 
@@ -98,9 +73,6 @@ emper_fibril void search(const std::string& path) {
 		DIE_MSG("read of " << path << " failed: " << strerror(-bytes_read));
 	}
 
-out:
-	delete buf;
-
 	// We do not need to close registered files they are closed automatically if a
 	// new file is registered at their slot.
 	// And the slot is returned when the RegisteredFile is dropped.