[SunRay-Users] EXTERNAL:Re: EXTERNAL: Sun Desktop AccessClient (SDAC / soft client) poor performance

Bob Doolittle Robert.Doolittle at Sun.COM
Tue Mar 2 00:42:33 EET 2010


MTU settings sound more plausible than uttsc to me.
uttsc should not affect latency as measured by utcapture - that's purely 
a metric measured between the X server and the client.

-Bob

Nishimura, Scott L (IT Solutions) wrote:
> Devin,
>
>   I'll have to defer to more knowledgeable members of this list.  The
> performance you describe, however, is suspiciously similar to what we
> experienced a few years back before we had tuned our MTU settings [we
> ultimately settled on 1470]:  when going through a PowerPoint stack,
> we'd get 5-second delays in screen redraw.
>
> The only other time I've seen something like this was when I was using
> PCSC [PC Smart Card] 1.0 and when I got a normal workload on the SRS,
> pcscd started taking up 6% of the CPU and users would see many 5-second
> delays during their session.
>
> Scott
>
> -----Original Message-----
> From: sunray-users-bounces at filibeto.org
> [mailto:sunray-users-bounces at filibeto.org] On Behalf Of Devin Nate
> Sent: Monday, March 01, 2010 2:27 PM
> To: SunRay-Users mailing list
> Subject: Re: [SunRay-Users] EXTERNAL:Re: EXTERNAL: Sun Desktop
> AccessClient (SDAC / soft client) poor performance
>
> Ahh, now that's something we haven't done yet... packet capture of the
> uttsc data. So far we've done a packet capture of the dtu<-->srss and
> compared with sdac<-->srss, and we couldn't see any difference there.
>
> I'll report observations asap.
>
> That said, would a difference in uttsc traffic to the terminal servers
> cause utcapture to indicate a higher latency?
>
> Thanks,
> Devin
>
>
>
> -----Original Message-----
> From: sunray-users-bounces at filibeto.org
> [mailto:sunray-users-bounces at filibeto.org] On Behalf Of Nishimura, Scott
> L (IT Solutions)
> Sent: Monday, March 01, 2010 3:16 PM
> To: SunRay-Users mailing list
> Subject: Re: [SunRay-Users] EXTERNAL:Re: EXTERNAL: Sun Desktop Access
> Client (SDAC / soft client) poor performance
>
> Devin,
>
>   How about if you run a truss or pstack or similar troubleshooting tool
> on uttsc and compare the results between the actual DTU and SDAC?
>
> Does your sniffer test show excessive retransmissions?
>
> Also, what MTU size is being used?  Too large [> 1470?] could lead to
> fragmentation; too small [< 500] could lead to "laggy" performance
> [we've run into that before on a physical DTU before].
>
>
> Scott
>
> -----Original Message-----
> From: sunray-users-bounces at filibeto.org
> [mailto:sunray-users-bounces at filibeto.org] On Behalf Of Devin Nate
> Sent: Monday, March 01, 2010 2:06 PM
> To: lars.tunkrans at bredband.net; SunRay-Usersmailing list
> Subject: EXTERNAL:Re: [SunRay-Users] EXTERNAL: Sun Desktop Access Client
> (SDAC / soft client) poor performance
>
> Hi Lars;
>
> I completely agree... the problem is, the DTU and SDAC clients are on
> identical networks... in fact, I've taken the cable out of a perfect DTU
> and put it into a PC. I was thinking perhaps QoS or something tagging
> the udp packages.
>
> The PCs have Intel nic's. I'm tracking down totally different
> architectures. Our core is all Cisco networking gear. We're looking to
> setup a host on the same LAN directly connected to the core, that said
> we had some hosts in the datacenter getting latency of 500.000, gig
> connected but on a different subnet.
>
> All that aside, the Sun DTU's work perfect on the same network. We're
> going through everything with a fine tooth comb, but I'm not optimistic.
>
> More thoughts?
>
> Thanks,
> Devin
>
>
>
>
> -----Original Message-----
> From: sunray-users-bounces at filibeto.org
> [mailto:sunray-users-bounces at filibeto.org] On Behalf Of Lars Tunkrans
> Sent: Monday, March 01, 2010 2:36 PM
> To: SunRay-Users mailing list
> Subject: Re: [SunRay-Users] EXTERNAL: Sun Desktop Access Client (SDAC /
> soft client) poor performance
>
> 2010-03-01 20:31, Devin Nate skrev:
>   
>> I'm really appreciating the ideas, please keep them coming?
>>
>> Thanks,
>> Devin
>>    
>>     
>
> Hi,
>
>    When I experience  laggy  screen updates  on a DTU  ist is usually 
> becase there is
> a problem with the network .
>
>   As the list can testify:
>
>    One returning problem is  Low end  flaky  L2 switches  with a  
> gigabit input from the CORE  switch
> and 100Mbit  link out to the DTU.  These L2 switches  drops UDP  packets
>
> and forces  the DTU
> to ask for them again .  Hence  the Laggy  screen updates.
>
>
>
>    Now heres a long shot.....
>
> if you are using  mainly the same  brand  pc ,  do they all have the 
> same  LAN Card / CHipset ?
> There are many kinds of problems  with  Chinese  wierdo combines  of  
> PHY  / MAC   chipsets.
> They come up with new combinations every week just to be able to 
> produce  the motherboard  5 cents
> cheaper.
>
>    Should  you try   an  Intel  Pro1000  GT  Desktop adaptor ?   I think
>
> so.
>
>    
> http://www.intel.com/products/desktop/adapters/pro1000gt/pro1000gt-overv
> iew.htm
>
>    This is probably the the most stable  ethernet card today,  since  
> 3COM  stopped making
>    ethernet cards.
>
>
>     Did you try to attach  the PC  directly to core switch  yet ?
>
>      //Lars
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