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: Fri, 28 Oct 2016 22:04:33 +0200 [thread overview]
Message-ID: <69acd529-fc75-bd74-17ae-bedd8796e706@users.sourceforge.net> (raw)
In-Reply-To: <e264883f-d1b9-4bf3-aa9f-45fce5dab18e@users.sourceforge.net>
>>> So back to the original task for you: Show me in the generated output where the benefits are.
I can offer another bit of information for this software development discussion.
The following build settings were active in my "Makefile" for this Linux test case.
…
HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O0 -fomit-frame-pointer -std=gnu89
…
The afffected source files can be compiled for the processor architecture "x86_64"
by a tool like "GCC 6.2.1+r239849-1.5" from the software distribution
"openSUSE Tumbleweed" with the following command example.
my_original=${my_build_dir}unchanged/test/ \
&& my_fixing=${my_build_dir}patched/test/ \
&& mkdir -p ${my_original} ${my_fixing} \
&& my_cc=/usr/bin/gcc-6 \
&& my_module=drivers/md/raid1.s \
&& git checkout next-20161014 \
&& make -j6 O="${my_original}" CC="${my_cc}" HOSTCC="${my_cc}" allmodconfig "${my_module}" \
&& git checkout next_usage_of_seq_putc_in_md_raid_1 \
&& make -j6 O="${my_fixing}" CC="${my_cc}" HOSTCC="${my_cc}" allmodconfig "${my_module}" \
&& diff -u "${my_original}${my_module}" "${my_fixing}${my_module}" > "${my_build_dir}assembler_code_comparison_$(date -I)_3.diff"
The generated file got the size "25.4 KiB" this time. I guess that only
the following two diff hunks are interesting then to show desired effects
for the suggested software refactoring around data output of a single character
(instead of a similar string).
…
@@ -4402,10 +4402,6 @@
.LC19:
.string "%s"
.zero 61
- .align 32
-.LC20:
- .string "]"
- .zero 62
.text
.p2align 4,,15
.type raid1_status, @function
@@ -4564,8 +4560,8 @@
movq $rcu_lock_map, %rdi #,
call lock_release #
movq %r14, %rdi # seq,
- movq $.LC20, %rsi #,
- call seq_printf #
+ movl $93, %esi #,
+ call seq_putc #
addq $16, %rsp #,
popq %rbx #
popq %r12 #
…
* Is this kind of assembler code comparison useful to clarify relevant
differences further?
* Are any software development concerns left over for such a transformation?
Regards,
Markus
next prev parent reply other threads:[~2016-10-28 20:04 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
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 [this message]
2016-10-17 14:00 ` Hannes Reinecke
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