1 Nov
2016
1 Nov
'16
12:13 a.m.
On Monday, October 31, 2016 3:55:30 PM EDT Chris Caudle wrote:
The problem exists in Windows (7), and in Linux with Jack or Pulse.
For example simply going to a test-tone website and playing the
tones in Windows, or in Linux via Pulse. Jack isn't running in
that case but maybe Pulse is starting Jack... Must check.
And certainly with any Linux Jack app it does it (MusE, JackRack etc).
I tried running Jack with hpet clock source (I had to run as root), no luck.
Here is my cpuinfo with two and four cores:
Can you spot anything? Thanks for your help!
Tim.
[With two CPU cores:]
========================
cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 30
model name : Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz
stepping : 5
microcode : 0x3
cpu MHz : 2668.000
cache size : 8192 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm
constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc
aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm
sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs :
bogomips : 5333.11
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 30
model name : Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz
stepping : 5
microcode : 0x3
cpu MHz : 2668.000
cache size : 8192 KB
physical id : 0
siblings : 2
core id : 1
cpu cores : 2
apicid : 2
initial apicid : 2
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm
constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc
aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm
sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs :
bogomips : 5333.11
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
[With four CPU cores:]
========================
cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 30
model name : Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz
stepping : 5
microcode : 0x3
cpu MHz : 2668.000
cache size : 8192 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm
constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc
aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm
sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs :
bogomips : 5333.44
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 30
model name : Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz
stepping : 5
microcode : 0x3
cpu MHz : 2668.000
cache size : 8192 KB
physical id : 0
siblings : 4
core id : 1
cpu cores : 4
apicid : 2
initial apicid : 2
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm
constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc
aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm
sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs :
bogomips : 5333.44
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
processor : 2
vendor_id : GenuineIntel
cpu family : 6
model : 30
model name : Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz
stepping : 5
microcode : 0x3
cpu MHz : 2668.000
cache size : 8192 KB
physical id : 0
siblings : 4
core id : 2
cpu cores : 4
apicid : 4
initial apicid : 4
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm
constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc
aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm
sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs :
bogomips : 5333.44
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
processor : 3
vendor_id : GenuineIntel
cpu family : 6
model : 30
model name : Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz
stepping : 5
microcode : 0x3
cpu MHz : 2668.000
cache size : 8192 KB
physical id : 0
siblings : 4
core id : 3
cpu cores : 4
apicid : 6
initial apicid : 6
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm
constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc
aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm
sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs :
bogomips : 5333.44
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
On Mon, October 31, 2016 2:18 pm, termtech wrote:
Yeah, I know. Very strange. Single card. No other audio enabled.
Onboard audio disabled.
With playback only, there were crackles and pops and eventually, depending
on the test tone, it could lapse into horrible permanent screeching.
With full duplex audio in -> audio out (live effect or pass-through
situation mentioned above), eventually the slow drifting was noticed.
This test suggests maybe one core is handling playback and
another is handling record, and they are drifting in time such that
every 15 minutes it drifts into that bad noise and then drifts out again.
How else to explain? It sounds like exactly what happens when you
actually purposely force a playback DAC to a slightly different
sample rate than the recording ADC, in a pass-through situation.
Recall: My Delta1010-LT card was not OK in my new
PC...
...
This time however, I noticed something: When
using the card in an 'effect'
situation, where audio input is passed through to an audio output, either
directly or with some effect, horrible noise would appear after 15
minutes and then... slowly drift into working again for 15 minutes,
and then slowly drift into noise again for 15 minutes, then
working again for 15 minutes and so on.
This was a HUGE clue. This slow drifting in and out of noise is familiar.
It is instantly recognizable to me (as should you) as a synchronization
problem, not a PCI voltage or bus problem.
This is with a single 1010LT card, correct?
I think that clock sync problems should not be possible with a properly
configured single card. Can you show the clock configuration for your card
some way? Maybe screen
capture of envy24control? I think that there should be options for
internal clock, S/PDIF recovered clock, or word clock input for the
output. If you are using external S/PDIF connected devices you will
probably need to verify that there is one device set to use internal
clock, and all other devices synchronized to the received S/PDIF clock.
No trouble there. It's on internal 44KHz clock, not spdif or external clock.
And I tried flipping the setting a few times. And rebooting.
I even unplugged the Delta 1010's multi-connector containing the sync
and spdif cables, in case interference was getting in.
So... on this
replacement PC there is a setting in the BIOS for the number
of CPU cores to activate. The cheaper original new PC had NO such
setting.
Physical cores, or virtual cores? Virtual cores would usually be called
simultaneous multi-threading (SMT, generic term) or hyper-threading (Intel
trademark). Enabling hyper-threading can increase latency, disabling and
measuring change in worst case latency is usually one of the things to
check when tuning a machine for low latency.
I had even researched these CPUs and had read
that it is possible that
the CPU Clock signals can be independent for each core, thus causing
some synchronization problems.
There are multiple things that can accurately be described as a "clock" in
modern CPU's, some of which change with core speed if using power savings
modes which modify the CPU frequency. Competently designed modern
software would not use those timers and would use a core frequency
invariant timer.
At this point I'm not sure if this a clock
signal sync problem or a
timer/counter problem. I had also read that 'local' timers/counters
can be a problem with multi-core CPUs - that time is not quite the
same in each core.
That is correct, you can research how that is handled in modern CPU's when
software needs accurate timekeeping. It is basically a solved problem,
although using inappropriate timers could be a problem if using software
which was developed many years ago.
IIRC Someone told me that a quad core is two
chips each with two cores ??
That tended to be true in 2005, not so much these days. Most processors
with up to 12 cores, sometimes more, are single die now. Those which are
not do not tend to show up in desktop computers.
Can anyone shed some more light on these
multi-core problems?
Comments welcome, please!
I personally have not experienced any problems with multi-core processors.
When you enable all four cores, what is in the contents of /proc/cpuinfo?
First impression is that this is a problem with the card synchronization
settings, but I have no idea how changing the CPU configuration could
affect that.
What software is running? Is this system using jackd, or direct ALSA
access, or something else?