[lustre-discuss] LNET Self-test

Jon Tegner tegner at foi.se
Tue Feb 7 02:13:42 PST 2017

Probably doing something wrong here, but I tried to test only READING 
with the following:

export LST_SESSION=$$
lst new_session read
lst add_group servers at o2ib
lst add_group readers at o2ib
lst add_batch bulk_read
lst add_test --batch bulk_read --concurrency 12 --from readers --to 
servers \
brw read check=simple size=1M
lst run bulk_read
lst stat servers & sleep 10; kill $!
lst end_session

which in my case gives:

[LNet Rates of servers]
[R] Avg: 3633     RPC/s Min: 3633     RPC/s Max: 3633     RPC/s
[W] Avg: 7241     RPC/s Min: 7241     RPC/s Max: 7241     RPC/s
[LNet Bandwidth of servers]
[R] Avg: 2.29     MB/s  Min: 2.29     MB/s  Max: 2.29     MB/s
[W] Avg: 3608.44  MB/s  Min: 3608.44  MB/s  Max: 3608.44  MB/s

it seems strange that it should report non zero numbers in the [W] 
positions? Specially that bandwidth is low in the [R] position (since I 
explicitly demanded "read")? Also note that if I change "brw read" to 
"brw write" in the script above the results are "reversed" in the sense 
that it reports the higher number regarding bandwidth in the [R] 
position. That is "brw read" reports (almost) the expected bandwidth in 
the [W]-position, whereas "brw write" reports it in the [R]-position.

This is on CentOS-6.5/Lustre-2.5.3. Will try 7.3/2.9.0 later.


On 02/06/2017 05:45 PM, Oucharek, Doug S wrote:
> Try running just a read test and then just a write test rather than having both at the same time and see if the performance goes up.

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