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All daq nodes should run the cpu frequency governor in either "ondemand" or "performance" mode.
As of this writing (May 2, 2022) the daq node daq-xpp-cam02 is not running the cpu frequency governor in "performance" mode.It appears to be running in "ondemand" mode, which "tries to use the slowest speed as much as possible, but quickly switches up or down when needed."
The epix10a2m requires "performance" mode for correct operation.
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Hi,
For example in /cds/group/pcds/dist/pds/boot/daq-det-pgp01 we have the following:
for f in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do
echo "performance" > $f
done
This is set for all the machines that are running an epix10ka2m:
daq-det-pgp01
daq-mec-pgp02
daq-mfx-pgp01
daq-xcs-pgp02
daq-xpp-pgp02
Dan |
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$ hostname daq-xpp-cam02 $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor ondemandperformance $ =========== $ hostname daq-xpp-dss03 $ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor powersave powersave powersave powersave powersave powersave $ |
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As of this writing (May 6, 2022), hyperthreading is enabled on drp-neh-cmp001 and drp-neh-cmp007 (and perhaps elsewhere).
Arguments
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for hyperthreading
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Ric Claus writes:
I can say that the state of the hyperthreading flag is not important for running with trigger rates of 71 KHz and below, but I’m not ready to say that we can dispense with it for 1 MHz running.
Arguments against hyperthreading
On May 6, 2022, at 5:52 PM, Perazzo, Amedeo <perazzo@slac.stanford.edu> wrote:
I had the rhino thought when we installed drp-srcf so we decided to enable hyperthreading (the AMD one, which has a different name) on the new system and we asked Chris (O'Grady) to give it another try. After Chris' tests we decided there was no value in hyperthreading, even on AMD, and we disabled it entirely on drp-srcf. Chris, do you remember?
On May 6, 2022, Chris O'Grady wrote:
I had forgotten, but you are correct Amedeo. My results (for mpi-psana analysis) are here
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It looks like an early test suggested HT helped, but when I tried to reproduce it later on I couldn’t, so we disabled it. Many years ago I also benchmarked some quantum-chemistry code with/without HT and it didn’t help there either
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On March 26, 2015, Chris Ford wrote:
To:
chris
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| language | text |
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| title | March 2015 email (LCLS-I) |
| collapse | true |
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pcds-daq-l
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Subject:
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SXR:
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hyperthreading
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enabled
...
on
...
daq-sxr-cam02
...
and
...
'03?
...
Folks,
...
While
...
testing
...
the
...
Andor
...
camera
...
I
...
learned
...
that
...
some
...
DAQ
...
nodes
...
were
...
known
...
to
...
work
...
better
...
than
...
others
...
for
...
this
...
USB-based
...
device.
...
Tomy
...
writes,
...
"One
...
example
...
I
...
remember
...
is
...
that
...
daq-sxr-cam01
...
was
...
okay
...
to
...
run
...
for
...
hours,
...
but
...
daq-sxr-cam{02,03}
...
would
...
hang
...
after
...
some
...
minutes."
...
Today
...
I
...
took
...
a
...
closer
...
look,
...
and
...
I
...
noticed
...
that
...
hyperthreading
...
seems
...
to
...
be
...
enabled
...
on
...
daq-sxr-cam02
...
and
...
'03,
...
where
...
Andor
...
fails.
...
Hyperthreading
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seems
...
to
...
be
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*disabled*
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on
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daq-sxr-cam01,
...
where
...
Andor
...
runs
...
well
...
.
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