This patch series improves the performance of read/write/erase operations
on sdcards.
This is done by increasing the maximum buffer size that is worked on.
>From 1 byte (master) to 512 bytes (first commit) to larger than 512
(adma commit).
Testing on my system with fio I see the following rough performance
values in MiB/s.
read write readwrite
master: 6 6 3/ 3
first commit: 51 43 23/ 23
second commit: 392 180 144/143
Tested on a 2GiB raw image with:
fio --filename=/dev/mmcblk0 --direct=1 --runtime=60 --time_based --bs=128k
--rw={mode}
The adma values are somewhat unstable but always >100MiB/s, I'm not sure
why but I guess it has something to do with the host side caching.
The third commit fixes the DATA_STAT_AFTER_ERASE bit in SCR and
introduces an option to allow to erase blocks to 0x00.
The fourth commit optimizes block erase when erase-blocks-as-zero=true
is used, by passing the zeroing request down the to the block device.
Erasing 2GiB now takes 0.1s instead of 26s.
Signed-off-by: Christian Speich <[email protected]>
---
Changes in v2:
- Properly set DATA_STAT_AFTER_ERASE in SCR
- Add erase-blocks-as-zero option to allow the user to switch between
0x00 and 0xFF for erased blocks.
- Link to v1:
https://lore.kernel.org/qemu-devel/[email protected]
---
Christian Speich (4):
hw/sd: Switch from byte-wise to buf+len read/writes
hw/sd/sdhci: Don't use bounce buffer for ADMA
hw/sd/sdcard: Add erase-blocks-as-zero option.
hw/sd/sdcard: Optimize erase blocks as zero.
hw/sd/core.c | 16 +--
hw/sd/sd.c | 308 +++++++++++++++++++++++++++++++++++++++++------------
hw/sd/sdhci.c | 102 ++++++++++--------
include/hw/sd/sd.h | 13 +--
4 files changed, 307 insertions(+), 132 deletions(-)
---
base-commit: e7c1e8043a69c5a8efa39d4f9d111f7c72c076e6
change-id: 20250912-sdcard-performance-b4-d908bbb5a004
Best regards,
--
Christian Speich <[email protected]>
