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From 88e527d9fbbbe8d05e45f6db8a151d22e7f973d3 Mon Sep 17 00:00:00 2001
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From: Gerd Hoffmann <kraxel@redhat.com>
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Date: Thu, 30 Jun 2022 17:28:40 +0200
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Subject: [PATCH] virtio-blk: use larger default request size
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RH-Author: Gerd Hoffmann <kraxel@redhat.com>
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RH-MergeRequest: 8: virtio-blk: use larger default request size
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RH-Commit: [1/1] df68a35a0d02fb91f61eca9e9342ae5f13f99803
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RH-Bugzilla: 2101787
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RH-Acked-by: Oliver Steffen <osteffen@redhat.com>
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RH-Acked-by: Pawel Polawski <ppolawsk@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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Bump default from 8 to 64 blocks. Using 8 by default leads
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to requests being splitted on qemu, which slows down boot.
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Some (temporary) debug logging added showed that almost all
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requests on a standard fedora install are less than 64 blocks,
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so that should bring us back to 1.15 performance levels.
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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(cherry picked from commit 46de2eec93bffa0706e6229c0da2919763c8eb04)
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---
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src/hw/virtio-blk.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/src/hw/virtio-blk.c b/src/hw/virtio-blk.c
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index 929ba887..9b4a05a4 100644
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--- a/src/hw/virtio-blk.c
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+++ b/src/hw/virtio-blk.c
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@@ -95,7 +95,7 @@ virtio_blk_op(struct disk_op_s *op, int write)
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blk_num_max = (u16)max_io_size / vdrive->drive.blksize;
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else
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/* default blk_num_max if hardware doesnot advise a proper value */
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- blk_num_max = 8;
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+ blk_num_max = 64;
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if (op->count <= blk_num_max) {
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virtio_blk_op_one_segment(vdrive, write, sg);
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--
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2.31.1
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