0b6715de3c
- kvm-migration-Handle-block-device-inactivation-failures-.patch [bz#2177957] - kvm-migration-Minor-control-flow-simplification.patch [bz#2177957] - kvm-migration-Attempt-disk-reactivation-in-more-failure-.patch [bz#2177957] - kvm-nbd-server-push-pending-frames-after-sending-reply.patch [bz#2035712] - kvm-nbd-server-Request-TCP_NODELAY.patch [bz#2035712] - Resolves: bz#2177957 (Qemu core dump if cut off nfs storage during migration) - Resolves: bz#2035712 ([qemu] Booting from Guest Image over NBD with TLS Is Slow)
56 lines
2.2 KiB
Diff
56 lines
2.2 KiB
Diff
From 17c5524ada3f2ca9a9c645f540bedc5575302059 Mon Sep 17 00:00:00 2001
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From: Eric Blake <eblake@redhat.com>
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Date: Mon, 3 Apr 2023 19:40:47 -0500
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Subject: [PATCH 5/5] nbd/server: Request TCP_NODELAY
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Eric Blake <eblake@redhat.com>
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RH-MergeRequest: 274: nbd: improve TLS performance of NBD server
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RH-Bugzilla: 2035712
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
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RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>
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RH-Commit: [2/2] 092145077756cda2a4f849c5911031b0fc4a2134 (ebblake/qemu-kvm)
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Nagle's algorithm adds latency in order to reduce network packet
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overhead on small packets. But when we are already using corking to
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merge smaller packets into transactional requests, the extra delay
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from TCP defaults just gets in the way (see recent commit bd2cd4a4).
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For reference, qemu as an NBD client already requests TCP_NODELAY (see
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nbd_connect() in nbd/client-connection.c); as does libnbd as a client
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[1], and nbdkit as a server [2]. Furthermore, the NBD spec recommends
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the use of TCP_NODELAY [3].
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[1] https://gitlab.com/nbdkit/libnbd/-/blob/a48a1142/generator/states-connect.c#L39
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[2] https://gitlab.com/nbdkit/nbdkit/-/blob/45b72f5b/server/sockets.c#L430
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[3] https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md#protocol-phases
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CC: Florian Westphal <fw@strlen.de>
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Signed-off-by: Eric Blake <eblake@redhat.com>
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Message-Id: <20230404004047.142086-1-eblake@redhat.com>
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Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
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(cherry picked from commit f1426881a827a6d3f31b65616c4a8db1e9e7c45e)
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Signed-off-by: Eric Blake <eblake@redhat.com>
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---
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nbd/server.c | 1 +
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1 file changed, 1 insertion(+)
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diff --git a/nbd/server.c b/nbd/server.c
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index a5edc7f681..6db124cf53 100644
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--- a/nbd/server.c
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+++ b/nbd/server.c
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@@ -2738,6 +2738,7 @@ void nbd_client_new(QIOChannelSocket *sioc,
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}
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client->tlsauthz = g_strdup(tlsauthz);
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client->sioc = sioc;
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+ qio_channel_set_delay(QIO_CHANNEL(sioc), false);
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object_ref(OBJECT(client->sioc));
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client->ioc = QIO_CHANNEL(sioc);
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object_ref(OBJECT(client->ioc));
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--
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2.39.1
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