Hi Chris,
I posted them a couple of days ago but here they are
net.ipv4.tcp_rmem = 10240 87380 12582912
net.ipv4.tcp_wmem = 10240 87380 12582912
net.core.rmem_default = 12582912
net.core.wmem_default = 12582912
net.ipv4.tcp_congestion_control = bic
cheers
alessandra
On 26/02/11 12:13, Christopher J. Walker wrote:
> On 26/02/11 11:28, Alessandra Forti wrote:
>> Correction TW in the inbound test does go up to 9-10MB. I have to try
>> with a bigger file.
>>
>> cheers
>> alessandra
>>
>> On 26/02/11 11:15, Alessandra Forti wrote:
>>> Hi,
>>>
>>> based on the observation that Manchester is much better at receiving
>>> data than serving them, I've done some simple transfer tests between 3
>>> T1s back and forth using lcg-cp. Taking these 3 with different
>>> characteristics:
>>>
>>> *TW-FTT:* extremely slow <100KBs I had to use a smaller file to
>>> complete the tests, coming back the rate shoots to 600 KBs with peaks
>>> of 2.2MBs it would be interesting to try with a bigger file in this
>>> direction.
>>> *RAL:* average oscillating between 5MBs-11MBs both directions,
>>> *IN2P3-CC:* slow sending data there 1.1MBs but extremely fast getting
>>> them back 100MBs.
>>>
>>> I run tcpdump during the transfers and used tcptrace to analyse the
>>> output. I put the output of tcptrace here
>>> http://ks.tier2.hep.manchester.ac.uk/T2/sonar and some quick view of
>>> the reults below:
>>>
>>> I can probably become more systematic using a gridftp transfer tool
>>> and avoid SRM negotiation which also have seems to vary in length and
>>> also is unpredictable on which data server will return.
>>>
>>> My questions are:
>>>
>>> * Why the second column has always 12 bytes in the outbound tests?
>>> Shouldn't there be an appropriate resizing of windows in both
>>> directions as it happens when I copy back the data?
>>>
>>> * Windows are not going above few tenths of KB. In the old TCP
>>> protocol they cannot go above 64KB. This was changed to keep up with
>>> GB connections and now TCP windows can go up to 1GB size. However it
>>> doesn't seem the case here despite the MB put in sysctl.conf.
>>
>
> What settings are actually in use at the moment?
>
> Specifically, can you run:
>
> sysctl net.core.rmem_max
> sysctl net.core.wmem_max
> sysctl net.ipv4.tcp_wmem
> sysctl net.ipv4.tcp_wmem
>
> and also
> sysctl net.ipv4.tcp_congestion_control
>
> on your gridftp server.
>
> Chris
>
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