Re: [LTP] NUMA system and get_a_numa_node()

[Wanlong Gao <gaowanlong@cn.fujitsu.com>]

On 11/27/2014 10:42 AM, Han Pingtian wrote:
> On Wed, Nov 26, 2014 at 01:53:36PM +0100, Cyril Hrubis wrote:
>> Hi!
>>> We have a system which only has one NUMA node. When trying to run ksm02
>>> on it, becase the code calling get_allowed_nodes() with a count 2 as
>>> below:
>>>
>>>  972 /* Warning: *DO NOT* use this function in child */
>>>  973 unsigned int get_a_numa_node(void (*cleanup_fn) (void))
>>>  974 {              
>>>  975         unsigned int nd1, nd2;
>>>  976         int ret; 
>>>  977                        
>>>  978         ret = get_allowed_nodes(0, 2, &nd1, &nd2);
>>>  979         switch (ret) { 
>>>  980         case 0:
>>>  981                 break;
>>>  982         case -3:
>>>  983                 tst_brkm(TCONF, cleanup_fn, "requires a NUMA system.");
>>>
>>> it always failed with "requires a NUMA system.".
>>>
>>> I think a NUMA system may have only one node, right? If so, could we
>>> change the count to 1?
>>
>> Hmm, are you sure that the testcases are actually applicable to a system
>> with only one node?
>>
>> Because what the testcases do in the setup is to write 1 to
>> /sys/kernel/mm/ksm/merge_across_nodes so I would expect that the test
>> needs at least two nodes...
>>
> I think if there is only one NUMA node, then this is a special case for
> this testcase, it'll test if set "merge_across_nodes" to 1, any problem
> will be triggered.
> 
> I have tried to change the node count to 1 in get_allowed_nodes() and
> recompiled ksm02. It works successfully.
> 


Do you think ONLY ONE NODE can be called NUMA?

http://en.wikipedia.org/wiki/Non-uniform_memory_access

Thanks,
Wanlong Gao

> Thanks.
> 
> 
> ------------------------------------------------------------------------------
> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
> from Actuate! Instantly Supercharge Your Business Reports and Dashboards
> with Interactivity, Sharing, Native Excel Exports, App Integration & more
> Get technology previously reserved for billion-dollar corporations, FREE
> http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk
> _______________________________________________
> Ltp-list mailing list
> Ltp-list@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/ltp-list
> 


------------------------------------------------------------------------------
Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
from Actuate! Instantly Supercharge Your Business Reports and Dashboards
with Interactivity, Sharing, Native Excel Exports, App Integration & more
Get technology previously reserved for billion-dollar corporations, FREE
http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk
_______________________________________________
Ltp-list mailing list
Ltp-list@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/ltp-list