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 (commit 1-3) 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 fifth commit fixes the DATA_STAT_AFTER_ERASE bit in SCR and
introduces an option to allow to erase blocks to 0x00.
The sixth 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 <c.speich@avm.de>
---
Changes in v3:
- Rebase onto master, updating read/write path for newly added RBMP
- Split up commit 1 into multiple commits
- change interface to allow "short" read/writes that are continued
by the core later by calling again
- Link to v2: https://lore.kernel.org/qemu-devel/20251202-sdcard-performance-b4-v2-0-d42490b11322@avm.de
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/20250919-sdcard-performance-b4-v1-0-e1037e481a19@avm.de
---
Christian Speich (6):
hw/sd: Switch read/write primitive to buf+len
hw/sd/sd: Allow multi-byte read/write for generic paths
hw/sd/sd: Use multi-byte/block writes for block path
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 | 26 +++--
hw/sd/sd.c | 333 ++++++++++++++++++++++++++++++++++++++++-------------
hw/sd/sdhci.c | 102 ++++++++--------
include/hw/sd/sd.h | 22 ++--
4 files changed, 341 insertions(+), 142 deletions(-)
---
base-commit: 28a6ca268c2cd3718b5bf24c2d97e3d1e95fc604
change-id: 20250912-sdcard-performance-b4-d908bbb5a004
Best regards,
--
Christian Speich <c.speich@avm.de>