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From: SF Markus Elfring <elfring@users.sourceforge.net>
To: ltp@lists.linux.it
Subject: [LTP] MD-RAID: Use seq_putc() in three status functions?
Date: Mon, 17 Oct 2016 13:10:18 +0200	[thread overview]
Message-ID: <a0f96e19-fa24-8507-2b77-344a342113aa@users.sourceforge.net> (raw)
In-Reply-To: <c2500336-5848-66c3-ecf0-1ade04decf75@suse.de>

>> * Is a string pointer often longer than a byte?
>>
> Always.

I have got doubts for this specific information.


> (Which up to now I thought was basic programming knowledge...)

By the way:
Run time environments still exist where the size of a pointer can be also
just one byte, don't they?


>> How many results would we like to clarify from various hardware
>> and software combinations?
>>
> See above. At the moment _any_ test result from your side would do.

I imagine that another single result might not be representative.
How many lessons from test statistics will usually be also relevant here?


>> How important are the mentioned functions for you within the Linux
>> programming interface so far?
>>
> Not very. The interface is only used in a slow path, and the execution
> time doesn't affect I/O performance in any way.

Thanks for another interesting information.


>>> Case in point: with your patch the x86_64 compiler generates nearly
>>> identical code for driver/md/raid1.c, but with one instruction _more_
>>> after your patch has been applied.
>>
>> Which software versions and command parameters did you try out
>> for this information (from an unspecified run time environment)?
>>
> # gcc --version
> gcc (SUSE Linux) 4.8.5

Thanks for this detail.

* Did you choose any special optimisation settings for your quick check?

* Will any compilation results matter if "optimisation" would be
  switched off there?


> I'm still waiting from results from your side.

Would any other software developers or testers dare to add related information?

Regards,
Markus

  reply	other threads:[~2016-10-17 11:10 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <566ABCD9.1060404@users.sourceforge.net>
     [not found] ` <786843ef-4b6f-eb04-7326-2f6f5b408826@users.sourceforge.net>
     [not found]   ` <92c52f1d-d151-cea6-e9ac-31378e6862d0@users.sourceforge.net>
     [not found]     ` <1475771699.1914.10.camel@perches.com>
     [not found]       ` <77fb6fdc-7480-8607-0af1-42f73c125b9d@users.sourceforge.net>
     [not found]         ` <688764a4-072d-2faf-37ba-a222b190a5d9@suse.de>
     [not found]           ` <59d71170-c48d-a084-c748-b6ab74a2bee4@users.sourceforge.net>
     [not found]             ` <1e151094-e228-5307-ae2f-b376b31f5628@suse.de>
     [not found]               ` <83e720c6-9037-a3c1-6e83-27505805f37f@users.sourceforge.net>
     [not found]                 ` <2cc42b2f-1f1a-e95c-91fa-54e1dd3b6d49@suse.de>
2016-10-17  9:00                   ` [LTP] MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring
2016-10-17  9:50                     ` Hannes Reinecke
2016-10-17 11:10                       ` SF Markus Elfring [this message]
2016-10-17 11:32                         ` Bernd Petrovitsch
2016-10-17 11:43                           ` SF Markus Elfring
2016-10-17 14:01                             ` Hannes Reinecke
2016-10-17 14:30                               ` SF Markus Elfring
2016-10-17 15:33                                 ` Hannes Reinecke
2016-10-17 16:08                                   ` SF Markus Elfring
2016-10-17 17:18                                     ` Hannes Reinecke
2016-10-18 18:20                                       ` SF Markus Elfring
2016-10-20 12:24                                         ` SF Markus Elfring
2016-10-28 20:04                                           ` SF Markus Elfring
2016-10-17 14:00                         ` Hannes Reinecke

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