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Subject: Re: [PATCH 11/11] selftests: net/fcnal: Reduce client timeout
To:     David Ahern <dsahern@gmail.com>, Jakub Kicinski <kuba@kernel.org>,
        Shuah Khan <shuah@kernel.org>, David Ahern <dsahern@kernel.org>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Ido Schimmel <idosch@nvidia.com>,
        Seth David Schoen <schoen@loyalty.org>,
        netdev@vger.kernel.org, linux-kselftest@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <cover.1633520807.git.cdleonard@gmail.com>
 <516043441bd13bc1e6ba7f507a04362e04c06da5.1633520807.git.cdleonard@gmail.com>
 <3ed2262e-fce2-c587-5112-e4583cd042ed@gmail.com>
From:   Leonard Crestez <cdleonard@gmail.com>
Message-ID: <c48ea9e2-acdc-eb11-a4b0-35474003fcf3@gmail.com>
Date:   Thu, 7 Oct 2021 00:26:57 +0300
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On 06.10.2021 18:01, David Ahern wrote:
> On 10/6/21 5:47 AM, Leonard Crestez wrote:
>> Reduce default client timeout from 5 seconds to 500 miliseconds.
>> Can be overridden from environment by exporting NETTEST_CLIENT_TIMEOUT=5
>>
>> Some tests need ICMP timeouts so pass an explicit -t5 for those.
>>
>> Signed-off-by: Leonard Crestez <cdleonard@gmail.com>
>> ---
>>   tools/testing/selftests/net/fcnal-test.sh | 17 +++++++++++------
>>   1 file changed, 11 insertions(+), 6 deletions(-)
>>
> 
> The problem with blindly reducing the timeouts is running the script on
> a loaded server. Some tests are expected to timeout while for tests a
> timeout is a failure.

Keeping the default value "5" would be fine as long as it is possible to 
override externally and get fast results on a mostly-idle machine.

Placing a default value in the environment which is overriden by certain 
tests achieves that.

In theory it would also be possible for fcnal-test.sh to parse as 
"--timeout" option and pass it into every single test but that solution 
would cause much more code churn.

Having default values in environment variables that can still be 
overridden by command-line arguments is a common pattern in many tools. 
It also avoids having to pass-through every flag through every 
intermediate wrapper.

--
Regards,
Leonard