PasTim;691469 Wrote: 
> Apologies if this has been addressed before, but I have been looking at
> the Touch CPU load (using 'top') with PCM vs FLAC on 24/96 tracks. 
> 
> .....
> 
> With PCM, process sirq-net-rx/0 is running at well over 50% CPU. 
> That's a lot.  With FLAC, it's down to around 10-15%.  Total CPU is
> around 70-90% with PCM, and 40-60% with FLAC.  I have to admit I am
> astonished at how high the CPU load is with PCM.
> 
> As I understand it, the theory is that the CPU load needs to be as low
> as possible.  Doesn't that imply FLAC is better than PCM, at least at
> high bit rates?
> 
One for linux experts out there....

The reason I was initially suspicious of the cpu loads was that the
screen scrolling (once only) on the Touch seemed slow and jerky when
using my linux set-up.

I wondered whether there was some problem with my PC's network card
set-up under linux. So,

1) I ran LMS on my Windows 7 setup and the cpu loads were considerably,
and consistently, lower, for the same tracks - still higher for PCM than
FLAC, but around 50% for PCM and 30% for FLAC.

2) I ran my Ubuntu setup (same PC, dual boot) and the cpu loads shot up
again.

3) I found out how to use 'ethtool' on Ubuntu to see what my network
card was set up to do.  It seem to be set up the same as my W7, ie no
flow control, 1000Mbs, full duplex, autonegotiation on

4) I reduced the speed to 100Mbs and turned off autonegotiation

5) CPU loads much better, as per Windows 7

6) I raised the network speed back again, back to 1000Mbs,
autonegotiation on

7) CPU loads still much better.

You don't believe me. Who would? I didn't believe it either.

I ran it several times,  with the same result, then created a start-up
script on Ubuntu to make this switch to lower and then faster speeds at
boot, and it worked!

Anyone got any idea what is happening here?

After all that I still find FLAC transmission gives lower CPU loads
than PCM which must be good, No?


-- 
PasTim

Server on Windows 7 Ultimate 64 bit, 2 CPU, 2GHz, 4GB, FLAC files. Touch
on Ethernet (in another room).  Analogue out over 'a bit of wire' to
ageing Quad Hi-Fi. An old (wireless) laptop controls the server using
Chrome.
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