docs/designs/phosphor-hwmon-io-uring.md

7 - Brandon Kim ([brandonkim@google.com](mailto:brandonkim@google.com), brandonk)
8 - William A. Kennington III ([wak@google.com](mailto:wak@google.com), wak)
18 [phosphor-hwmon](https://github.com/openbmc/phosphor-hwmon)) that may have this
22 ## Background and References
30 method for preventing sensors from blocking all other sensor reads and D-Bus if
31 they do not report failures quickly enough in the phosphor-hwmon repository
32 ([link to change](https://gerrit.openbmc.org/c/openbmc/phosphor-hwmon/+/24337)).
42 - [phosphor-hwmon](https://github.com/openbmc/phosphor-hwmon)
43 - [phosphor-nvme](https://github.com/openbmc/phosphor-nvme)
44 - [dbus-sensors](https://github.com/openbmc/dbus-sensors)
45 - any other appropriate repository
48 phosphor-hwmon repository, which is easier to implement than adding asynchronous
49 sensor reads into dbus-sensors.
58 In the phosphor-hwmon repository, the primary files that will require
60 …pp](https://github.com/openbmc/phosphor-hwmon/blob/master/sensor.cpp)/[.hpp](https://github.com/op…
62 …p](https://github.com/openbmc/phosphor-hwmon/blob/master/mainloop.cpp)/[.hpp](https://github.com/o…
63 as well the addition of a caching layer for the results from the sensor reads.
66 entries, iterates through all sensors and calls `_ioAccess->read(...)` for each
70 operation non-blocking by using an io_uring wrapper. A caching layer will be
75                Interface Layer
76 +--------------------------------------------+
78 |   +------------+         +-------------+   |
82 |   +-----+------+         +-------+-----+   |
84 +---------|------------------------|---------+
87 +---------+------------------------+---------+
91 +---------^------------------------^---------+
93   +-------v-------+       +--------v-------+
95   |phosphor-hwmon |       |  dbus-sensors  |
97   +-------^-------+       +--------^-------+
98           | <--------------------- | <------- caching layer at this level
99  +--------v------------------------v--------+
103  +----------^---------------------^---------+
105        +----v-----+         +-----v----+
109        +----------+         +----------+
129 track of any pre-existing submissions so that multiple SQEs for the same sensor
135 SQE requests, a non-blocking operation, at once instead of being blocked by slow
138 to process any returned CQEs, a non-blocking operation as well.
149 supports true asynchronous IO for un-buffered reads. Furthermore, there are a
150 number of ways that the IO submission can end up blocking - for example, if
159 This project would impact all OpenBMC developers of openbmc/phosphor-hwmon
160 initially. It has improved the latency performance of phosphor-hwmon; throughput