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* mvebu: Patch kernel to fix SATA write performance regression Add an upstream patch that fixes SATA write speed regression that appeared in kernel 5.9. Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com> * Create 0001-Revert-block-simplify-set_init_blocksize-to-regain-l.patch Co-authored-by: Igor Pečovnik <igorpecovnik@users.noreply.github.com>
71 lines
2.9 KiB
Diff
71 lines
2.9 KiB
Diff
From b2b8b700c7be053eeadc0b3e172e18a0d148fa5e Mon Sep 17 00:00:00 2001
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From: Maxim Mikityanskiy <maxtram95@gmail.com>
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Date: Tue, 26 Jan 2021 21:46:47 +0200
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Subject: [PATCH] Revert "block: simplify set_init_blocksize" to regain lost
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performance
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The cited commit introduced a serious regression with SATA write speed,
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as found by bisecting. This patch reverts this commit, which restores
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write speed back to the values observed before this commit.
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The performance tests were done on a Helios4 NAS (2nd batch) with 4 HDDs
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(WD8003FFBX) using dd (bs=1M count=2000). "Direct" is a test with a
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single HDD, the rest are different RAID levels built over the first
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partitions of 4 HDDs. Test results are in MB/s, R is read, W is write.
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| Direct | RAID0 | RAID10 f2 | RAID10 n2 | RAID6
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----------------+--------+-------+-----------+-----------+--------
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9011495c9466 | R:256 | R:313 | R:276 | R:313 | R:323
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(before faulty) | W:254 | W:253 | W:195 | W:204 | W:117
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----------------+--------+-------+-----------+-----------+--------
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5ff9f19231a0 | R:257 | R:398 | R:312 | R:344 | R:391
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(faulty commit) | W:154 | W:122 | W:67.7 | W:66.6 | W:67.2
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----------------+--------+-------+-----------+-----------+--------
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5.10.10 | R:256 | R:401 | R:312 | R:356 | R:375
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unpatched | W:149 | W:123 | W:64 | W:64.1 | W:61.5
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----------------+--------+-------+-----------+-----------+--------
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5.10.10 | R:255 | R:396 | R:312 | R:340 | R:393
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patched | W:247 | W:274 | W:220 | W:225 | W:121
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Applying this patch doesn't hurt read performance, while improves the
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write speed by 1.5x - 3.5x (more impact on RAID tests). The write speed
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is restored back to the state before the faulty commit, and even a bit
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higher in RAID tests (which aren't HDD-bound on this device) - that is
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likely related to other optimizations done between the faulty commit and
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5.10.10 which also improved the read speed.
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Upstream status: accepted to 5.11.
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https://www.spinics.net/lists/linux-block/msg64471.html
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Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
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Fixes: 5ff9f19231a0 ("block: simplify set_init_blocksize")
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Cc: Christoph Hellwig <hch@lst.de>
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Cc: Jens Axboe <axboe@kernel.dk>
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---
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fs/block_dev.c | 10 +++++++++-
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1 file changed, 9 insertions(+), 1 deletion(-)
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diff --git a/fs/block_dev.c b/fs/block_dev.c
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index 3b8963e228a1..235b5042672e 100644
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--- a/fs/block_dev.c
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+++ b/fs/block_dev.c
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@@ -130,7 +130,15 @@ EXPORT_SYMBOL(truncate_bdev_range);
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static void set_init_blocksize(struct block_device *bdev)
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{
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- bdev->bd_inode->i_blkbits = blksize_bits(bdev_logical_block_size(bdev));
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+ unsigned int bsize = bdev_logical_block_size(bdev);
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+ loff_t size = i_size_read(bdev->bd_inode);
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+
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+ while (bsize < PAGE_SIZE) {
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+ if (size & bsize)
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+ break;
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+ bsize <<= 1;
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+ }
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+ bdev->bd_inode->i_blkbits = blksize_bits(bsize);
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}
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int set_blocksize(struct block_device *bdev, int size)
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--
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2.30.0
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