IDE: Addressing slow PIO throughput

[PATCH 0/1] IDE: Addressing slow PIO throughput

Lev Kujawski posted 1 patch 1 year, 11 months ago

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git fetch https://github.com/patchew-project/qemu tags/patchew/20220602213904.19533-1-lkujaw@member.fsf.org

Maintainers: John Snow <jsnow@redhat.com>

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

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[PATCH 0/1] IDE: Addressing slow PIO throughput

Posted by Lev Kujawski 1 year, 11 months ago

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(-)

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2.34.1