Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
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>
 <c48ea9e2-acdc-eb11-a4b0-35474003fcf3@gmail.com>
 <65ae97e3-73c1-3221-96fe-6096a8aacfa1@gmail.com>
From:   Leonard Crestez <cdleonard@gmail.com>
Message-ID: <d7ac5d58-1e59-a657-a51b-4d757f7552ca@gmail.com>
Date:   Thu, 7 Oct 2021 23:52:39 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.13.0
MIME-Version: 1.0
In-Reply-To: <65ae97e3-73c1-3221-96fe-6096a8aacfa1@gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 07.10.2021 04:17, David Ahern wrote:
> On 10/6/21 3:26 PM, Leonard Crestez wrote:
>> 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.
> 
> 5 is the default for nettest.c; the test script passes in -t1 for all tests.

An explicit -t is only passed for some of the tests

$ grep -c nettest.*-r tools/testing/selftests/net/fcnal-test.sh
243
$ grep -c nettest.*-t tools/testing/selftests/net/fcnal-test.sh
15

>> 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.
> 
> I do not agree with env variables here.

Would you agree with adding an option to fcnal-test.sh which decreases 
timeouts passed to nettest client calls?