Messages in this thread | | | Date | Wed, 23 May 2012 17:50:03 +0200 | From | Ingo Molnar <> | Subject | Re: Plumbers: Tweaking scheduler policy micro-conf RFP |
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* Joe Perches <joe@perches.com> wrote:
> On Wed, 2012-05-23 at 17:03 +0200, Ingo Molnar wrote: > > * Chen <hi3766691@gmail.com> wrote: > > > > > Still you are just trying to said that your code is not bloated? > > > Up to over 500K for a cpu scheduler. Laughing > > > > Where did you get that 500K from? You are off from the truth > > almost by an order of magnitude. > > > > Here's the scheduler size on Linus's latest tree, on 64-bit > > defconfig's: > > > > $ size kernel/sched/built-in.o > > text data bss dec hex filename > > 83611 10404 2524 96539 1791b kernel/sched/built-in.o > > > > That's SMP+NUMA, i.e. everything included. > > > > The !NUMA !SMP UP scheduler, if you are on a size starved > > ultra-embedded device, is even smaller, just 22K: > > > > $ size kernel/sched/built-in.o > > text data bss dec hex filename > > 19882 2218 148 22248 56e8 kernel/sched/built-in.o > > Here's an allyesconfig x86-32
allyesconfig includes a whole lot of debugging code so it's a pretty meaningless size test.
> $ size kernel/sched/built-in.o > text data bss dec hex filename > 213892 10856 65832 290580 46f14 kernel/sched/built-in.o > > But that's not the only sched related code. > > In a 1000 cpu config, there also an extra 500+ bytes per cpu > in printk (I don't think that's particularly important btw)
A 1000 cpu piece of hardware will have a terabyte of RAM or more. 0.5K per CPU is reasonable.
> kernel/printk.c adds: > > static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); > > Maybe #ifdefing this when !CONFIG_PRINTK would reduce size > a little in a few cases. I've attached a trivial suggested patch.
That might make sense for the ultra-embedded.
Still 500K is an obviously nonsensical number.
Thanks,
Ingo
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