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

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Message-ID: <bf6c54f1-7af4-747c-a58b-be13ab74563e@users.sourceforge.net>
Date:   Mon, 17 Oct 2016 18:08:09 +0200
From:   SF Markus Elfring <elfring@...rs.sourceforge.net>
To:     Hannes Reinecke <hare@...e.de>, linux-raid@...r.kernel.org
Cc:     Bernd Petrovitsch <bernd@...rovitsch.priv.at>,
        Christoph Hellwig <hch@....de>,
        Guoqing Jiang <gqjiang@...e.com>, Jens Axboe <axboe@...com>,
        Joe Perches <coupons@...ches.com>,
        Mike Christie <mchristi@...hat.com>,
        Neil Brown <neilb@...e.com>, Shaohua Li <shli@...nel.org>,
        Tomasz Majchrzak <tomasz.majchrzak@...el.com>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org, kbuild-all@...org,
        ltp@...ts.linux.it
Subject: Re: MD-RAID: Use seq_putc() in three status functions?

>> * Would you really like to know under which circumstances data processing
>>   will be faster for a single character instead of using a string pointer
>>   and corresponding two characters?
>>
> It's not a problem of the interface, it's a problem of the resulting code
> (ie assembler output).

How do you think about to discuss concrete generated code any further?


> We can discuss all we like, if the compiler decides to throw in
> an optimisation none of the arguments even apply.

Would it make sense to clarify assembler output with optimisation switched off?

Do you eventually care for code from non-optimising compilers?


>> * Will it occasionally be useful to avoid the storage for another string literal?
>>
> Occasionally: yes.
> In this particular case: hardly.

I am curious when such a software design aspect can become more relevant.
Would it be nice to get rid of three questionable string terminators (null bytes)
for example?

Regards,
Markus