[Nut-upsdev] A lot of EAGAIN (Resource temporarily unavailable) using nutdrv_qx

Thu May 26 17:57:23 UTC 2016

Hello,

I have a Salicru UPS connected by USB using nutdrv_qx driver. As I see
that it was using too much CPU time (or at least, too much for what I
think it should be normal), I used strace to see what is was using,
and got a lot of lines like these:

%<------------%<------------%<------------%<------------
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 1 (out [4], left {0, 944})
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffdca143278) = 0
write(2, "  42.693227\t", 12)           = 12
write(2, "read: (224.4 224.4 224.4 007 50.0 13.7 --.- 00001001\n", 53) = 53
write(2, "  42.693517\t", 12)           = 12
write(2, "ups_infoval_set: non numerical value [ups.temperature:
--.-]\n", 61) = 61
%<------------%<------------%<------------%<------------

I downloaded the code and patched and compiled myself. Using some
"sleeps" it goes better, but not so fine I would like:

%<------------%<------------%<------------%<------------
write(2, "send: QS\n", 9)               = 9
nanosleep({0, 100000000}, NULL)         = 0
ioctl(4, USBDEVFS_SUBMITURB, 0x7ffc0d2c66e0) = 0
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 1 (out [4], left {0, 564})
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = 0
nanosleep({0, 100000000}, NULL)         = 0
ioctl(4, USBDEVFS_SUBMITURB, 0x7ffc0d2c66e0) = 0
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = 0
nanosleep({0, 100000000}, NULL)         = 0
ioctl(4, USBDEVFS_SUBMITURB, 0x7ffc0d2c66e0) = 0
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 0 (Timeout)
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 1 (out [4], left {0, 923})
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = 0
nanosleep({0, 100000000}, NULL)         = 0
ioctl(4, USBDEVFS_SUBMITURB, 0x7ffc0d2c66e0) = 0
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 1 (out [4], left {0, 891})
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = 0
nanosleep({0, 100000000}, NULL)         = 0
ioctl(4, USBDEVFS_SUBMITURB, 0x7ffc0d2c66e0) = 0
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 1 (out [4], left {0, 993})
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = 0
nanosleep({0, 100000000}, NULL)         = 0
ioctl(4, USBDEVFS_SUBMITURB, 0x7ffc0d2c66e0) = 0
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = -1 EAGAIN (Resource
temporarily unavailable)
select(5, NULL, [4], NULL, {0, 1000})   = 1 (out [4], left {0, 916})
ioctl(4, USBDEVFS_REAPURBNDELAY, 0x7ffc0d2c66a8) = 0
write(2, "  34.057452\t", 12)           = 12
write(2, "read: (226.5 226.5 226.5 007 50.0 13.7 --.- 00001001\n", 53) = 53
write(2, "  34.057802\t", 12)           = 12
write(2, "ups_infoval_set: non numerical value [ups.temperature:
--.-]\n", 61) = 61
%<------------%<------------%<------------%<------------

Is this the right behaviour? If not, could it goes better using
libusb-1.0? Are the port to libusb-1.0 in the roadmap?

Attached are a zip file with the full output of the original and the
patched version of the driver, if you need more information. I also
attach the patch applied.

Thank you very much for your time.
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