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 Tue, 29 Dec 2020 19:53:37 +0300 (MSK)
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 <72c07be7cadc1e78c9394bbc8f1bb64b1a4a4a0c.1609259010.git.artemreyt@tarantool.org>
From: Leonid Vasiliev <lvasiliev@tarantool.org>
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Date: Tue, 29 Dec 2020 19:53:28 +0300
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Subject: Re: [Tarantool-patches] [PATCH 1/3] test: tarantool -e test add
 more details and avoid busy loop
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To: Artem Starshov <artemreyt@tarantool.org>, Alexander Turenko <alexander.turenko@tarantool.org>
Cc: tarantool-patches@dev.tarantool.org


Hi! Thank you for the patch.
See a comment bellow:

On 29.12.2020 19:25, Artem Starshov wrote:
> From: Alexander Turenko <alexander.turenko@tarantool.org>
> 
> Background: the test fails on waiting the process termination, but
> surprisingly only on GitHub hosted runners.
> 
> My guess is that the process becomes zombie, but we don't collect it.
> 
> A busy loop is not good in general. It is better to pass execution to
> other fibers if there is nothing to do. This way the waiting will not
> eat 100% CPU time.
> 
> Added collect more details in tarantool -e 'assert(false)' test.
> ---
>   .../gh-4983-tnt-e-assert-false-hangs.test.lua       | 13 ++++++++++++-
>   1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/test/app-tap/gh-4983-tnt-e-assert-false-hangs.test.lua b/test/app-tap/gh-4983-tnt-e-assert-false-hangs.test.lua
> index 656fe212b..ff3281e0f 100755
> --- a/test/app-tap/gh-4983-tnt-e-assert-false-hangs.test.lua
> +++ b/test/app-tap/gh-4983-tnt-e-assert-false-hangs.test.lua
> @@ -31,6 +31,7 @@ local function wait_process_completion(pid, timeout)
>               process_completed = true
>               break
>           end
> +        fiber.sleep(0.01)
>       end
>       return process_completed
>   end
> @@ -74,8 +75,18 @@ local res = tap.test('gh-4983-tnt-e-assert-false-hangs', function(test)
>       local process_completed = wait_process_completion(pid,
>               process_waiting_timeout)
>   
> +    local details

It looks like the details are only interesting in case of failure. Maybe
we will collect it only in this case?

> +    pcall(function()
> +        details = {
> +            cmdline = fio.open(('/proc/%d/cmdline'):format(pid),
> +                               {'O_RDONLY'}):read(1000000),
> +            status = fio.open(('/proc/%d/status'):format(pid),
> +                              {'O_RDONLY'}):read(1000000),
> +        }
> +    end)
>       test:ok(process_completed,
> -            ('tarantool process with pid = %d completed'):format(pid))
> +            ('tarantool process with pid = %d completed'):format(pid),
> +            details)
>   
>       -- Kill process if hangs.
>       if not process_completed then ffi.C.kill(pid, 9) end
>