[MPTCP] Re: [PATCH mptcp-next v2] selftests: mptcp: add link failure test case

[Matthieu Baerts <matthieu.baerts at tessares.net>]

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Hi Florian,

On 09/10/2020 17:11, Florian Westphal wrote:
> Add a test case where a link fails with multiple subflows.
> The expectation is that MPTCP will transmit any data that
> could not be delivered via the failed link on another subflow.

Thank you for these modifications!

(...)

> @@ -279,14 +308,32 @@ run_tests()
>   	listener_ns="$1"
>   	connector_ns="$2"
>   	connect_addr="$3"
> -	rm_nr_ns1="${4:-0}"
> -	rm_nr_ns2="${5:-0}"
> -	speed="${6:-fast}"
> +	test_linkfail="$4"
> +	rm_nr_ns1="${5:-0}"
> +	rm_nr_ns2="${6:-0}"
> +	speed="${7:-fast}"
>   	lret=0
> +	oldin=""
> +
> +	if [ "$test_linkfail" -eq 1 ];then
> +		size=$((RANDOM%1024))
> +		size=$((size+1))
> +		size=$((size*128)) > +
> +		oldin=$(mktemp)
> +		cp "$cin" "$oldin"
> +		make_file "$cin" "client" $size
This will create one file up to 1024*128 KB = ~131MB when later using 
this command:


   dd if=/dev/urandom of="$name" bs=1024 count=$size


This file will be duplicated a few times later when doing the transfer:


   ( cat "$cin" ; (...) ; cat "$cin" ) | \
       tee "$cinsent" | \
       (...) $mptcp_connect (...) > "$cout"


If I am not mistaken, we then have:

- $cin = max 131MB: initial file
- $cinsent = 2 times $cin
- $sout = $cinsent

→ total: 5*$cin = max 655MB

Was it the intension? Could we reduce the maximum size while keeping the 
test valid?

On my side, /tmp is mounted in tmpfs and currently limited to 490M. Just 
to know if I need to increase the size of modify the selftest script :)

Cheers,
Matt
-- 
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