Re: High lock spin time for zone->lru_lock under extreme conditions

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, 12 Jan 2007, Ravikiran G Thirumalai wrote:

> > Does the system scale the right way if you stay within the bounds of node 
> > memory? I.e. allocate 1.5GB from each process?
> 
> Yes. We see problems only when we oversubscribe memory.

Ok in that case we can have more than 2 processors trying to acquire the 
same zone lock. If they have all exhausted their node local memory and are 
all going off node then all processor may be hitting the last node that 
has some  memory left which will cause a very high degree of contention.

Moreover mostatomic operations are to remote memory which is also 
increasing the problem by making the atomic ops take longer. Typically 
mature NUMA system have implemented hardware provisions that can deal with 
such high degrees of contention. If this is simply a SMP system that was
turned into a NUMA box then this is a new hardware scenario for the 
engineers.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux