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From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, stefanha@redhat.com, pbonzini@redhat.com,
	afaria@redhat.com, hreitz@redhat.com, qemu-devel@nongnu.org
Subject: [PATCH 4/5] aio-posix: Factor out adjust_polling_time()
Date: Fri,  7 Mar 2025 23:16:33 +0100	[thread overview]
Message-ID: <20250307221634.71951-5-kwolf@redhat.com> (raw)
In-Reply-To: <20250307221634.71951-1-kwolf@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 util/aio-posix.c | 77 ++++++++++++++++++++++++++----------------------
 1 file changed, 41 insertions(+), 36 deletions(-)

diff --git a/util/aio-posix.c b/util/aio-posix.c
index 95bddb9e4b..259827c7ad 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -600,6 +600,46 @@ static bool try_poll_mode(AioContext *ctx, AioHandlerList *ready_list,
     return false;
 }
 
+static void adjust_polling_time(AioContext *ctx, AioPolledEvent *poll,
+                                int64_t block_ns)
+{
+    if (block_ns <= poll->ns) {
+        /* This is the sweet spot, no adjustment needed */
+    } else if (block_ns > ctx->poll_max_ns) {
+        /* We'd have to poll for too long, poll less */
+        int64_t old = poll->ns;
+
+        if (ctx->poll_shrink) {
+            poll->ns /= ctx->poll_shrink;
+        } else {
+            poll->ns = 0;
+        }
+
+        trace_poll_shrink(ctx, old, poll->ns);
+    } else if (poll->ns < ctx->poll_max_ns &&
+               block_ns < ctx->poll_max_ns) {
+        /* There is room to grow, poll longer */
+        int64_t old = poll->ns;
+        int64_t grow = ctx->poll_grow;
+
+        if (grow == 0) {
+            grow = 2;
+        }
+
+        if (poll->ns) {
+            poll->ns *= grow;
+        } else {
+            poll->ns = 4000; /* start polling at 4 microseconds */
+        }
+
+        if (poll->ns > ctx->poll_max_ns) {
+            poll->ns = ctx->poll_max_ns;
+        }
+
+        trace_poll_grow(ctx, old, poll->ns);
+    }
+}
+
 bool aio_poll(AioContext *ctx, bool blocking)
 {
     AioHandlerList ready_list = QLIST_HEAD_INITIALIZER(ready_list);
@@ -682,42 +722,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
     /* Adjust polling time */
     if (ctx->poll_max_ns) {
         int64_t block_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - start;
-
-        if (block_ns <= ctx->poll.ns) {
-            /* This is the sweet spot, no adjustment needed */
-        } else if (block_ns > ctx->poll_max_ns) {
-            /* We'd have to poll for too long, poll less */
-            int64_t old = ctx->poll.ns;
-
-            if (ctx->poll_shrink) {
-                ctx->poll.ns /= ctx->poll_shrink;
-            } else {
-                ctx->poll.ns = 0;
-            }
-
-            trace_poll_shrink(ctx, old, ctx->poll.ns);
-        } else if (ctx->poll.ns < ctx->poll_max_ns &&
-                   block_ns < ctx->poll_max_ns) {
-            /* There is room to grow, poll longer */
-            int64_t old = ctx->poll.ns;
-            int64_t grow = ctx->poll_grow;
-
-            if (grow == 0) {
-                grow = 2;
-            }
-
-            if (ctx->poll.ns) {
-                ctx->poll.ns *= grow;
-            } else {
-                ctx->poll.ns = 4000; /* start polling at 4 microseconds */
-            }
-
-            if (ctx->poll.ns > ctx->poll_max_ns) {
-                ctx->poll.ns = ctx->poll_max_ns;
-            }
-
-            trace_poll_grow(ctx, old, ctx->poll.ns);
-        }
+        adjust_polling_time(ctx, &ctx->poll, block_ns);
     }
 
     progress |= aio_bh_poll(ctx);
-- 
2.48.1



  parent reply	other threads:[~2025-03-07 22:18 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-07 22:16 [PATCH 0/5] block: Improve writethrough performance Kevin Wolf
2025-03-07 22:16 ` [PATCH 1/5] file-posix: Support FUA writes Kevin Wolf
2025-03-10 10:41   ` Stefan Hajnoczi
2025-03-07 22:16 ` [PATCH 2/5] block/io: Ignore FUA with cache.no-flush=on Kevin Wolf
2025-03-10 10:42   ` Stefan Hajnoczi
2025-03-07 22:16 ` [PATCH 3/5] aio: Create AioPolledEvent Kevin Wolf
2025-03-10 10:55   ` Stefan Hajnoczi
2025-03-07 22:16 ` Kevin Wolf [this message]
2025-03-10 10:55   ` [PATCH 4/5] aio-posix: Factor out adjust_polling_time() Stefan Hajnoczi
2025-03-07 22:16 ` [PATCH 5/5] aio-posix: Separate AioPolledEvent per AioHandler Kevin Wolf
2025-03-10 10:55   ` Stefan Hajnoczi
2025-03-10 11:11     ` Kevin Wolf
2025-03-11  2:18       ` Stefan Hajnoczi
2025-03-10 10:55 ` [PATCH 0/5] block: Improve writethrough performance Stefan Hajnoczi

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