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From: Thomas Gleixner <tglx@linutronix.de>
To: Linus Torvalds <torvalds@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>,
	LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, Uros Bizjak <ubizjak@gmail.com>,
	linux-sparse@vger.kernel.org, lkp@intel.com,
	oe-kbuild-all@lists.linux.dev, Arnd Bergmann <arnd@kernel.org>
Subject: Re: [patch 5/9] x86: Cure per CPU madness on UP
Date: Mon, 18 Mar 2024 18:27:55 +0100	[thread overview]
Message-ID: <87le6fih5w.ffs@tglx> (raw)
In-Reply-To: <877ci3j80k.ffs@tglx>

On Sat, Mar 16 2024 at 02:11, Thomas Gleixner wrote:
> On Fri, Mar 15 2024 at 16:23, Linus Torvalds wrote:
> The amount of subtle SMP=n fallout has been kinda exponentially
> increasing over the years and it's just putting burden on the wrong
> people. TBH, I'm tired of this nonsense.

And for the fun of it I hacked Kconfig to allow a SMP=y NR_CPUS=1 build
and checked the size of vmlinux:

                64-bit          32-bit
SMP, NCPUS=1    38438400        22110177
UP              38393703        21682041
Delta              44697          428076
                     0.1%              2%              

The UP savings are not really impressive...

Let me look what it actually takes to do that.

Thanks,

        tglx


  parent reply	other threads:[~2024-03-18 17:27 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-04 10:12 [patch 0/9] x86: Cure tons of sparse warnings (mostly __percpu) Thomas Gleixner
2024-03-04 10:12 ` [patch 1/9] perf/x86/amd/uncore: Fix __percpu annotation Thomas Gleixner
2024-03-04 10:12 ` [patch 2/9] x86/msr: Prepare for including percpu.h Thomas Gleixner
2024-03-04 10:12 ` [patch 3/9] x86/msr: Add missing __percpu annotations Thomas Gleixner
2024-03-04 10:12 ` [patch 4/9] smp: Consolidate smp_prepare_boot_cpu() Thomas Gleixner
2024-03-04 10:12 ` [patch 5/9] x86: Cure per CPU madness on UP Thomas Gleixner
2024-03-15 16:17   ` Guenter Roeck
2024-03-15 16:42     ` Linus Torvalds
2024-03-15 17:02       ` Guenter Roeck
2024-03-15 17:40       ` Thomas Gleixner
2024-03-15 22:55         ` Thomas Gleixner
2024-03-15 23:23           ` Linus Torvalds
2024-03-16  1:11             ` Thomas Gleixner
2024-03-16  1:23               ` Linus Torvalds
2024-03-16 21:34                 ` Arnd Bergmann
2024-03-17 21:03               ` David Laight
2024-03-18 11:11               ` Thomas Gleixner
2024-03-18 17:27               ` Thomas Gleixner [this message]
2024-03-18 19:13                 ` Arnd Bergmann
2024-03-19 16:21                   ` Thomas Gleixner
2024-03-19 18:26                     ` Guenter Roeck
2024-03-16  0:56           ` Guenter Roeck
2024-03-20  8:58     ` Thomas Gleixner
2024-03-20 15:46       ` Guenter Roeck
2024-03-21 11:14         ` Thomas Gleixner
2024-03-21 14:06           ` Guenter Roeck
2024-03-21 16:49             ` Thomas Gleixner
2024-03-04 10:12 ` [patch 6/9] x86/uaccess: Add missing __force to casts in __access_ok() and valid_user_address() Thomas Gleixner
2024-03-04 10:12 ` [patch 7/9] x86/cpu: Use EXPORT_PER_CPU_SYMBOL_GPL() for x86_spec_ctrl_current Thomas Gleixner
2024-03-04 10:12 ` [patch 8/9] x86/cpu: Provide a declaration for itlb_multihit_kvm_mitigation Thomas Gleixner
2024-03-04 10:12 ` [patch 9/9] x86/callthunks: Use EXPORT_PER_CPU_SYMBOL_GPL() for per CPU variables Thomas Gleixner
2024-03-04 11:08 ` [patch 0/9] x86: Cure tons of sparse warnings (mostly __percpu) Ingo Molnar

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