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From: Alexey Dobriyan <adobriyan@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	mingo@redhat.com, Borislav Petkov <bp@alien8.de>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 1/4] sched: make nr_running() return 32-bit
Date: Fri, 14 May 2021 00:22:46 +0300	[thread overview]
Message-ID: <YJ2YphIIwMEQ5mIh@localhost.localdomain> (raw)
In-Reply-To: <YJz4TmZ7fmKFchRe@gmail.com>

On Thu, May 13, 2021 at 11:58:38AM +0200, Ingo Molnar wrote:
> 
> * Thomas Gleixner <tglx@linutronix.de> wrote:
> 

> > Just with the default config for one of my reference machines:
> > 
> >    text		data	bss	dec	 hex	 filename
> > 16679864	6627950	1671296	24979110 17d26a6 ../build/vmlinux-before
> > 16679894	6627950	1671296	24979140 17d26c4 ../build/vmlinux-after
> > ------------------------------------------------------------------------
> >      +30
> 
> Using '/usr/bin/size' to compare before/after generated code is the wrong 
> way to measure code generation improvements for smaller changes due to 
> default alignment creating a reserve of 'padding' bytes at the end of most 
> functions. You have to look at the low level generated assembly directly.

This is bloat-o-meter output with Fedora 33 .config:

This is how they look like, something gets bigger but total is smaller
(otherwise why would I send it). Apparently something got one 1 byte too
many and pushed padding.

add/remove: 0/0 grow/shrink: 6/21 up/down: 18/-42 (-24)
Function                                     old     new   delta
calc_load_fold_active                         50      56      +6
calc_load_nohz_start                         100     103      +3
calc_load_nohz_remote                         85      88      +3
calc_global_load_tick                         86      89      +3
pull_dl_task                                 901     903      +2
switched_from_dl                             613     614      +1
update_rt_migration                          165     164      -1
update_dl_migration                          141     140      -1
ttwu_do_activate                             181     180      -1
tick_nohz_idle_exit                          225     224      -1
tick_irq_enter                               227     226      -1
print_rt_rq.cold                             238     237      -1
print_rt_rq                                  413     412      -1
nr_iowait_cpu                                 31      30      -1
init_rt_rq                                   143     142      -1
show_stat                                   1745    1743      -2
nr_running                                    75      73      -2
nr_iowait                                     83      81      -2
get_cpu_iowait_time_us                       260     258      -2
get_cpu_idle_time_us                         260     258      -2
find_lock_later_rq                           507     505      -2
enqueue_task_rt                              777     775      -2
enqueue_task_dl                             2461    2459      -2
dequeue_rt_stack                             576     574      -2
menu_select                                 1492    1489      -3
__dequeue_dl_entity                          419     414      -5
init_dl_rq                                    88      81      -7
Total: Before=25729849, After=25729825, chg -0.00%

  reply	other threads:[~2021-05-13 21:22 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-22 20:02 [PATCH 1/4] sched: make nr_running() return 32-bit Alexey Dobriyan
2021-04-22 20:02 ` [PATCH 2/4] sched: make nr_iowait() return 32-bit value Alexey Dobriyan
2021-05-12 20:01   ` [tip: sched/core] sched: Make " tip-bot2 for Alexey Dobriyan
2021-04-22 20:02 ` [PATCH 3/4] sched: make nr_iowait_cpu() return 32-bit Alexey Dobriyan
2021-05-12 20:01   ` [tip: sched/core] sched: Make nr_iowait_cpu() return 32-bit value tip-bot2 for Alexey Dobriyan
2021-04-22 20:02 ` [PATCH 4/4] sched: make multiple runqueue task counters 32-bit Alexey Dobriyan
2021-05-12 19:36   ` Ingo Molnar
2021-05-12 20:01   ` [tip: sched/core] sched: Make " tip-bot2 for Alexey Dobriyan
2021-05-12 20:01 ` [tip: sched/core] sched: Make nr_running() return 32-bit value tip-bot2 for Alexey Dobriyan
2021-05-12 23:58 ` [PATCH 1/4] sched: make nr_running() return 32-bit Thomas Gleixner
2021-05-13  7:23   ` Alexey Dobriyan
2021-05-13  9:58   ` Ingo Molnar
2021-05-13 21:22     ` Alexey Dobriyan [this message]
2021-05-14 12:52     ` Thomas Gleixner
2021-05-14 18:18     ` Thomas Gleixner

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