Hi Sharp,
On 2023/8/25 15:10, Sharp Xia (夏宇彬) wrote:
On Thu, 2023-08-24 at 12:55 +0200, Ulf Hansson wrote:
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On Fri, 18 Aug 2023 at 04:45, <Sharp.Xia@xxxxxxxxxxxx> wrote:
From: Sharp Xia <Sharp.Xia@xxxxxxxxxxxx>
MMC does not set readahead and uses the default VM_READAHEAD_PAGES
resulting in slower reading speed.
Use the max_req_size reported by host driver to set the optimal
I/O size to improve performance.
This seems reasonable to me. However, it would be nice if you could
share some performance numbers too - comparing before and after
$subject patch.
Kind regards
Uffe
Signed-off-by: Sharp Xia <Sharp.Xia@xxxxxxxxxxxx>
---
drivers/mmc/core/queue.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index b396e3900717..fc83c4917360 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -359,6 +359,7 @@ static void mmc_setup_queue(struct mmc_queue
*mq, struct mmc_card *card)
blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
blk_queue_max_hw_sectors(mq->queue,
min(host->max_blk_count, host->max_req_size /
512));
+ blk_queue_io_opt(mq->queue, host->max_req_size);
if (host->can_dma_map_merge)
WARN(!blk_queue_can_use_dma_map_merging(mq->queue,
mmc_dev(hos
t)),
--
2.18.0
I test this patch on internal platform(kernel-5.15).
I patched this one and the test shows me a stable 11% performance drop.
Before:
echo 3 > proc/sys/vm/drop_caches && dd if=/data/1GB.img of=/dev/null
2048000+0 records in
2048000+0 records out
1048576000 bytes (0.9 G) copied, 3.912249 s, 256 M/s
After:
echo 3 > proc/sys/vm/drop_caches && dd if=/data/1GB.img of=/dev/null
2048000+0 records in
2048000+0 records out
1048576000 bytes (0.9 G) copied, 4.436271 s, 225 M/s
Before:
console:/ # echo 3 > /proc/sys/vm/drop_caches
console:/ # dd if=/mnt/media_rw/8031-130D/super.img of=/dev/null
4485393+1 records in
4485393+1 records out
2296521564 bytes (2.1 G) copied, 37.124446 s, 59 M/s
console:/ # cat /sys/block/mmcblk0/queue/read_ahead_kb
128
After:
console:/ # echo 3 > /proc/sys/vm/drop_caches
console:/ # dd if=/mnt/media_rw/8031-130D/super.img of=/dev/null
4485393+1 records in
4485393+1 records out
2296521564 bytes (2.1 G) copied, 28.956049 s, 76 M/s
console:/ # cat /sys/block/mmcblk0/queue/read_ahead_kb
1024
