Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1501886

Re: MD-RAID: Use seq_putc() in three status functions?

From SF Markus Elfring <elfring@users.sourceforge.net>
Newsgroups linux.kernel
Subject Re: MD-RAID: Use seq_putc() in three status functions?
Date 2016-10-17 13:20 +0200
Message-ID <ste7v-2Kh-17@gated-at.bofh.it> (permalink)
References (7 earlier) <st97Q-7NQ-9@gated-at.bofh.it> <staQi-wi-41@gated-at.bofh.it> <stbjk-YS-15@gated-at.bofh.it> <stc5H-1vh-19@gated-at.bofh.it> <stcS6-1MH-23@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

>> * 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

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] MD-RAID: Use seq_putc() in three status functions SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-16 10:30 +0200
  Re: [PATCH] MD-RAID: Use seq_putc() in three status functions Hannes Reinecke <hare@suse.de> - 2016-10-16 19:00 +0200
    Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-16 19:20 +0200
      Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-16 19:20 +0200
      Re: MD-RAID: Use seq_putc() in three status functions? Hannes Reinecke <hare@suse.de> - 2016-10-17 08:00 +0200
        Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-17 09:50 +0200
          Re: MD-RAID: Use seq_putc() in three status functions? Hannes Reinecke <hare@suse.de> - 2016-10-17 10:20 +0200
            Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-17 11:10 +0200
              Re: MD-RAID: Use seq_putc() in three status functions? Hannes Reinecke <hare@suse.de> - 2016-10-17 12:00 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-17 13:20 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-17 13:50 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? Hannes Reinecke <hare@suse.de> - 2016-10-17 16:10 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-17 16:40 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? Hannes Reinecke <hare@suse.de> - 2016-10-17 17:40 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-17 18:10 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? Hannes Reinecke <hare@suse.de> - 2016-10-17 19:20 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-18 20:30 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? SF Markus Elfring <elfring@users.sourceforge.net> - 2016-10-20 14:30 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? Bernd Petrovitsch <bernd@petrovitsch.priv.at> - 2016-10-17 14:20 +0200
                Re: MD-RAID: Use seq_putc() in three status functions? Hannes Reinecke <hare@suse.de> - 2016-10-17 16:10 +0200

csiph-web