> On Wed, 2008-10-22 at 08:35 -0700, Harry Edmon wrote:
>
>> I have a dual quad-core Xeon system running software
>> (
http://www.unidata.ucar.edu/software/ldm) that relays and processes
>> weather data through RPC calls, keeping a queue of data in a memory
>> mapped file. Up until 2.6.26 the system has run just fine (for example
>> 2.6.25.17). But starting with 2.6.26 through 2.6.27.2 the system runs
>> into a problem after approximately 24 hours. The symptom is that the
>> processing slows down to a crawl. Using "top" I can see that the System
>> time is up over 90%, with almost no User and Wait time. If I stop and
>> restart the software, most of the time it gets better - but sometimes it
>> takes a reboot to fix the problem. I have an identical system that does
>> just processing and ingesting data from remote systems, and it does not
>> have this problem. I have tried a number of different kernel
>> configurations, but they all show the same problem.
>>
>> I suspect a problem with SUNRPC. I notice that there were a large
>> number of SUNRPC patches in 2.6.26. I am looking for suggestions on how
>> to pin down which patches are causing the problem. Are there ways to
>> figure where in the kernel the time is being spent? I am will to work
>> on isolating the problem, but I need some suggestions on the best way to
>> do it given the large number of SUNRPC patches in 2.6.26 and the fact
>> that each experiment takes a day.
>>
>
> The kernel sunrpc interface is not exported to user land: the glibc code
> uses its own, entirely separate implementation of sunrpc.
>
> I cannot therefore see, how your application's RPC calls can be affected
> by kernel sunrpc changes.
>
> Cheers
> Trond
>
>
