Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)

On Thu, 2006-04-27 at 09:28 +0300, Pekka J Enberg wrote:
> On Thu, 27 Apr 2006, Nick Piggin wrote:
> > Not to dispute your conclusions or method, but I think doing a
> > defconfig or your personal config might be more representative
> > of % size increase of text that will actually be executed. And
> > that is the expensive type of text.
> 
> True but I was under the impression that Arjan thought we'd get text 
> savings with GCC 4.1 by making kfree() inline.

not savings in text size, I'll settle for the same size.
What we gain is less branches in the hotpath... eg a kfree that gets
optimized now has one less branch. Note that the branch predictor isn't
going to help you for these 100% cases, since the same branch "slot" is
shared between all callers; with this inline the branch predictor at
least gets to keep stats for each of the callers individually.
That is where the gain is....

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

---

• Follow-Ups:
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Adrian Bunk <[email protected]>

• References:
  • [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Hua Zhong <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: "Pekka Enberg" <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Arjan van de Ven <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Pekka J Enberg <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Arjan van de Ven <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Jörn Engel <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Arjan van de Ven <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Pekka J Enberg <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Arjan van de Ven <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Jörn Engel <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Pekka J Enberg <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Nick Piggin <[email protected]>
  • Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
    • From: Pekka J Enberg <[email protected]>

• Prev by Date: Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
• Next by Date: Re: Some Concrete AppArmor Questions - was Re: [RFC][PATCH 0/11] security: AppArmor - Overview
• Previous by thread: Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
• Next by thread: Re: [PATCH] likely cleanup: remove unlikely for kfree(NULL)
• Index(es):
  • Date
  • Thread

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]