linux-kernel - Re: [PATCH 3/6] selftests/resctrl: Simplify benchmark parameter passing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8f0fe5d7-d40a-4d04-ba19-3966505bd140@intel.com>
Date: Fri, 30 Aug 2024 09:01:05 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
CC: <fenghua.yu@...el.com>, <shuah@...nel.org>, <tony.luck@...el.com>,
	<peternewman@...gle.com>, <babu.moger@....com>,
	Maciej Wieczór-Retman <maciej.wieczor-retman@...el.com>,
	<linux-kselftest@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/6] selftests/resctrl: Simplify benchmark parameter
 passing

Hi Ilpo,

On 8/30/24 4:13 AM, Ilpo Järvinen wrote:
> On Thu, 29 Aug 2024, Reinette Chatre wrote:
> 
>> The benchmark used during the CMT, MBM, and MBA tests can be provided by
>> the user via (-b) parameter to the tests, if not provided the default
>> "fill_buf" benchmark is used.
>>
>> The "fill_buf" benchmark requires parameters and these are managed as
>> an array of strings.
>>
>> Using an array of strings to manage the "fill_buf" parameters is
>> complex because it requires transformations to/from strings at every
>> producer and consumer. This is made worse for the individual tests
>> where the default benchmark parameters values may not be appropriate and
>> additional data wrangling is required. For example, the CMT test
>> duplicates the entire array of strings in order to replace one of
>> the parameters.
>>
>> Replace the "array of strings" parameters used for "fill_buf" with a
>> struct that contains the "fill_buf" parameters that can be used directly
>> without transformations to/from strings. Make these parameters
>> part of the parameters associated with each test so that each test can
>> set benchmark parameters that are appropriate for it.
>>
>> Signed-off-by: Reinette Chatre <reinette.chatre@...el.com>
>> ---

...

> 
> If I didn't miss anything important, this change takes away the ability to
> alter fill_buf's parameters using -b option which to me felt the most
> useful way to use that parameter. The current code of course was lacks
> many safeguards for that case but still felt an useful feature.

hmmm ... thank you for pointing this out. I did not consider this use case.
I have never received feedback on how these tests are used  and
if folks even use "-b", for "fill_buf" parameter changes or something else.

> 
> I suggest that while parsing -b parameter, check if it starts with
> "fill_buf", and if it does, parse the argument into fill_buf_param in
> user_params which will override the default fill_buf parameters.
> 
> While parsing, adding new sanity checks wouldn't be a bad idea.
> 
> It might be some parameters might be better to be overridden always by the
> tests, e.g. "once" but specifying "operation" (W instead or R) or
> "buf_size" seems okay use cases to me.
> 

Will do. Thank you for the suggestion.

Reinette