From: Nguyen Chanh <nguyenchanh2201@gmail.com>
To: openbmc@lists.ozlabs.org
Subject: [c++] [hwmon] std::ifstream read file with timeout so long
Date: Tue, 6 Oct 2020 22:42:18 +0700 [thread overview]
Message-ID: <CAPGDkaHzu5UOES-irDLtu9jwLULyX9_BWAX7rgTPiaeXOT2ByA@mail.gmail.com> (raw)
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In https://github.com/openbmc/phosphor-hwmon => hwmonio.cpp , I saw we use
the std::ifstream to open and read a device sensor.
But, I met an issue with it. In case the sensor was disabled (Ex: the Fan
was unplugged), the std::ifstream read will take a long time . The timeout
in there is so long. It makes my system have a BIG delay in each checking
sensor.
Other observation : In case the sensor device is ready, the time for sensor
reading is expected.
Measuring std::ifstream reading:
In case unplugged sensor: 91385 microseconds
In case plugged sensor. : 507 microseconds
The patch to measure the std::ifstream reading, please see attachment !
Unexpected behavior you saw
The timeout in there is so long
Expected behavior
Do we have any better solution in this case? take less more timeout.
[image: Screen Shot 2020-10-03 at 11.32.36 AM.png]
--
*Nguyen Minh Chanh *
*Embedded Software Engineer *
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next reply other threads:[~2020-10-07 7:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 15:42 Nguyen Chanh [this message]
2020-10-07 15:24 ` [c++] [hwmon] std::ifstream read file with timeout so long Patrick Williams
2020-10-07 19:02 ` Anton Kachalov
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