[0/1] IDE: Addressing slow PIO throughput

Message

Lev Kujawski June 2, 2022, 9:39 p.m. UTC

Hello,

Is there any mechanism within QEMU for an emulated device to handle
string IO instructions (e.g., insw) directly?

I have noticed that PIO transfers seem rather slow (~240 kb/s) when
running QEMU on my computer, despite using a raw block device (SSD),
aio=io_uring, and file.cache.direct=on.  The attached patch improves
the rate by about 50% for me, and I would appreciate feedback on
whether this holds for others as well.

Kind regards,
Lev Kujawski

Lev Kujawski (1):
  hw/ide/core: Accumulate PIO output within io_buffer prior to pwritev

 hw/ide/core.c             | 62 ++++++++++++++++++++++++---------------
 include/hw/ide/internal.h |  1 +
 2 files changed, 39 insertions(+), 24 deletions(-)