All of lore.kernel.org
 help / color / mirror / Atom feed
From: Michael Tokarev <mjt@tls.msk.ru>
To: Andrew Hunter <ahh@google.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] core-kernel: use multiply instead of shifts in hash_64
Date: Tue, 10 Jul 2012 17:35:17 +0400	[thread overview]
Message-ID: <4FFC2F95.7080003@msgid.tls.msk.ru> (raw)
In-Reply-To: <20120702202534.GC844@google.com>

On 03.07.2012 00:25, Andrew Hunter wrote:
> diff --git a/include/linux/hash.h b/include/linux/hash.h
> index b80506b..daabc3d 100644
> --- a/include/linux/hash.h
> +++ b/include/linux/hash.h
> @@ -34,7 +34,9 @@
>  static inline u64 hash_64(u64 val, unsigned int bits)
>  {
>  	u64 hash = val;
> -
> +#if BITS_PER_LONG == 64
> +	hash *= GOLDEN_RATIO_PRIME_64;
> +#else
>  	/*  Sigh, gcc can't optimise this alone like it does for 32 bits. */

Hmm.  Does this comment make sense here now?

Thanks,

/mjt

  reply	other threads:[~2012-07-10 13:35 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-02 20:25 [PATCH 1/1] core-kernel: use multiply instead of shifts in hash_64 Andrew Hunter
2012-07-10 13:35 ` Michael Tokarev [this message]
2012-07-12 20:51   ` Andrew Hunter
  -- strict thread matches above, loose matches on Subject: below --
2012-06-15 22:18 Andrew Hunter

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4FFC2F95.7080003@msgid.tls.msk.ru \
    --to=mjt@tls.msk.ru \
    --cc=ahh@google.com \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.