Hi All,
we are currently working on a quite responce-time sensitive application. The actual "problem" we see, is that under (not yet fully found) conditions, there ocures a delay between the packet entering the NIC and the application to have access to it. (Tested with timestamps in the applications and reading the cable externally and internally) This delay occures only "sometimes" and is just to long to be ignored by the application. We talk about up to 12 milliseconds until the app gets the information which is quite a long time for our customers. We can see the delay being independent from hardware (Sparc or X86, intel ore broadcom NICs) and we are able to see it in all kind of Solaris versions (10 U2 -- until SNV)... Interesting enough, if we have just one "receeving" process (for example on one processor set with disabled interupt handling and its own 2-7 CPUs) we see ad 12ms Delay... If we have two streams and two receiving processes in this processer set we see a 6ms Delay. Additionally we see increasing crosscalls between cpus when this effect shows up. The problem is stripped down to a example application with a simple process sending data from one server another process on another server receiving the data and replying it with inserting timestamps. >From my observations, it can't be the pure hardware drivers, because the effect is independent from the NICs... (Customer also did test that on several different HW-Platforms) Having the pure sender/receiver the app is also not creating that effect.. (additionaly/off cause we don't see the effect when sending/receiving on the same system ... so our loopback interface is dooing a very well stack bypassing job) So what else can it be???? queuing on the IP side? Anny hint how to prevent/avoid the effect would be very helpful ! :-)... tks a lot in advance cu BUD
begin:vcard fn:Bertram Dorn n:Dorn;Bertram org:Sun Microsystems;Professional Services Delivery adr:;;Sonnenalle 1 ;Kirchheim;BY;85551;Germany email;internet:[email protected] title:Technology Specialist / Security Technology Ambassador tel;work:+49/89/46008/1350 tel;cell:+49/173/5633509 url:http://www.sun.com/de version:2.1 end:vcard
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