From: Ingo Molnar <mingo@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@amacapital.net>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-kselftest@vger.kernel.org, Dan Rue <dan.rue@linaro.org>
Subject: Re: [PATCH 2/2] selftests/x86/fsgsbase: Default to trying to run the test repeatedly
Date: Mon, 11 Feb 2019 13:51:46 +0100 [thread overview]
Message-ID: <20190211125146.GA66987@gmail.com> (raw)
In-Reply-To: <20190211124738.GA22391@sirena.org.uk>
* Mark Brown <broonie@kernel.org> wrote:
> On Mon, Feb 11, 2019 at 09:49:16AM +0100, Ingo Molnar wrote:
>
> > So this isn't very user-friendly either, previously it would run a
> > testcase and immediately provide output.
>
> > Now it's just starting and 'hanging':
>
> > galatea:~/linux/linux/tools/testing/selftests/x86> ./fsgsbase_64
>
> > I got bored and Ctrl-C-ed it after ~30 seconds.
>
> > How long is this supposed to run, and why isn't the user informed?
>
> On Intel systems I've got access to it's tended to only run for less
> than 10 seconds for me with excursions up to ~30s at most, I'd have
> projected it to be about a minute if the tests pass. However retesting
> with Debian's v4.19 kernel it seems to be running a lot more stably so
> we're now seeing it run to completion reliably when just one copy of the
> test is running.
>
> AFAICT it's not terribly idiomatic to provide much output, and anything
> that was per iteration would be *way* too spammy.
Certainly - but a "please wait" and updating the current count via \r
once every second isn't spammy.
> > Also, testcases should really be short, so I think a better approach
> > would be to thread the test-case and start an instance on every CPU. That
> > should also excercise SMP bugs, if any.
>
> Well, a *better* approach would be for the underlying issue that the
> test is finding to be fixed.
>
> I didn't look at adding more threads as the test case is already
> threaded, it does seem that running multiple copies simultaneously makes
> things reproduce more quickly so it's definitely useful though it's
> still taking multiple iterations.
multiple iterations are fine - waiting a minute with zero output on the
console isn't.
Thanks,
Ingo
prev parent reply other threads:[~2019-02-11 12:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-03 13:40 [PATCH 0/2] Make fsgsbase test more stable Mark Brown
2019-02-03 13:40 ` [PATCH 1/2] selftests/x86/fsgsbase: Indirect output through a wrapper function Mark Brown
2019-02-11 8:45 ` Ingo Molnar
2019-02-11 13:02 ` Mark Brown
2019-02-03 13:40 ` [PATCH 2/2] selftests/x86/fsgsbase: Default to trying to run the test repeatedly Mark Brown
2019-02-11 8:49 ` Ingo Molnar
2019-02-11 12:47 ` Mark Brown
2019-02-11 12:51 ` Ingo Molnar [this message]
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