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Antonio Pérez

2016-May-26 17:57 UTC

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

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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Charles Lepple

2016-Jun-01 03:01 UTC

head link

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

On May 26, 2016, at 1:57 PM, Antonio P?rez <aperez at skarcha.com>
wrote:> 
> 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})
How would you improve it?

There will definitely be a tradeoff between responsiveness and CPU usage.

I CC'd the author of nutdrv_qx - I think it could work to add a
"usleep" corresponding to the approximate size of the sent and
expected receive packet, but this would be different for 1.5 Mb/s and 12 Mb/s
USB devices.

You might also want to add timing numbers to the strace output (either
"-tt" or "-T").
> 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?
So far, there have not been any good arguments for libusb-1.0 that would offset
the amount of testing needed. Feel free to experiment, though. For timing
purposes, it should be sufficient to write a small loop that sends the command
for your UPS, and reads the response via libusb-1.0 (rather than trying to port
the entire NUT driver).

-- 
Charles Lepple
clepple at gmail

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