From 35c7c72601cee9692846de13117411d80b3d13f6 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 27 Nov 2024 20:10:19 -0500
Subject: ioq: Add an ioq_nop() operation for benchmarking

---
 src/ioq.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'src/ioq.h')

diff --git a/src/ioq.h b/src/ioq.h
index cb14be4..fce1d7f 100644
--- a/src/ioq.h
+++ b/src/ioq.h
@@ -22,6 +22,8 @@ struct ioq;
  * I/O queue operations.
  */
 enum ioq_op {
+	/** ioq_nop(). */
+	IOQ_NOP,
 	/** ioq_close(). */
 	IOQ_CLOSE,
 	/** ioq_opendir(). */
@@ -32,6 +34,16 @@ enum ioq_op {
 	IOQ_STAT,
 };
 
+/**
+ * ioq_nop() types.
+ */
+enum ioq_nop_type {
+	/** A lightweight nop that avoids syscalls. */
+	IOQ_NOP_LIGHT,
+	/** A heavyweight nop that involves a syscall. */
+	IOQ_NOP_HEAVY,
+};
+
 /**
  * The I/O queue implementation needs two tag bits in each pointer to a struct
  * ioq_ent, so we need to ensure at least 4-byte alignment.  The natural
@@ -54,6 +66,10 @@ struct ioq_ent {
 
 	/** Operation-specific arguments. */
 	union {
+		/** ioq_nop() args. */
+		struct ioq_nop {
+			enum ioq_nop_type type;
+		} nop;
 		/** ioq_close() args. */
 		struct ioq_close {
 			int fd;
@@ -97,6 +113,20 @@ struct ioq *ioq_create(size_t depth, size_t nthreads);
  */
 size_t ioq_capacity(const struct ioq *ioq);
 
+/**
+ * A no-op, for benchmarking.
+ *
+ * @ioq
+ *         The I/O queue.
+ * @type
+ *         The type of operation to perform.
+ * @ptr
+ *         An arbitrary pointer to associate with the request.
+ * @return
+ *         0 on success, or -1 on failure.
+ */
+int ioq_nop(struct ioq *ioq, enum ioq_nop_type type, void *ptr);
+
 /**
  * Asynchronous close().
  *
-- 
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