From: "Kok, Auke" <auke-jan.h.kok@intel.com>
To: Erez Zadok <ezk@cs.sunysb.edu>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, viro@ftp.linux.org.uk,
hch@infradead.org
Subject: Re: [PATCH 10/25] Unionfs: add un/likely conditionals on copyup ops
Date: Tue, 25 Sep 2007 21:32:44 -0700 [thread overview]
Message-ID: <46F9E0EC.3010105@intel.com> (raw)
In-Reply-To: <11907762093928-git-send-email-ezk@cs.sunysb.edu>
Erez Zadok wrote:
> Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
> ---
> fs/unionfs/copyup.c | 102 +++++++++++++++++++++++++-------------------------
> 1 files changed, 51 insertions(+), 51 deletions(-)
>
> diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
> index 23ac4c8..e3c5f15 100644
> --- a/fs/unionfs/copyup.c
> +++ b/fs/unionfs/copyup.c
> @@ -36,14 +36,14 @@ static int copyup_xattrs(struct dentry *old_lower_dentry,
>
> /* query the actual size of the xattr list */
> list_size = vfs_listxattr(old_lower_dentry, NULL, 0);
> - if (list_size <= 0) {
> + if (unlikely(list_size <= 0)) {
I've been told several times that adding these is almost always bogus - either it
messes up the CPU branch prediction or the compiler/CPU just does a lot better at
finding the right way without these hints.
Adding them as a blanket seems rather strange. Have you got any numbers that this
really improves performance?
Auke
next prev parent reply other threads:[~2007-09-26 4:33 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-26 3:09 [GIT PULL -mm] 00/25 Unionfs updates/cleanups/fixes Erez Zadok
2007-09-26 3:09 ` [PATCH 01/25] Unionfs: Simplify unionfs_get_nlinks Erez Zadok
2007-09-26 3:09 ` [PATCH 02/25] Unionfs: Remove unused #defines Erez Zadok
2007-09-26 3:09 ` [PATCH 03/25] Unionfs: display informational messages only if debug is on Erez Zadok
2007-09-26 8:36 ` Jan Engelhardt
2007-09-26 14:01 ` Erez Zadok
2007-09-26 15:24 ` Jan Engelhardt
2007-09-26 15:28 ` Erez Zadok
2007-09-26 3:09 ` [PATCH 04/25] Unionfs: cache-coherency fixes Erez Zadok
2007-09-26 3:09 ` [PATCH 05/25] Unionfs: cast page->index loff_t before shifting Erez Zadok
2007-09-26 8:31 ` Christoph Hellwig
2007-09-26 13:44 ` Erez Zadok
2007-09-26 3:09 ` [PATCH 06/25] Unionfs: minor coding style updates Erez Zadok
2007-09-26 3:09 ` [PATCH 07/25] Unionfs: add lower nameidata debugging support Erez Zadok
2007-09-26 3:09 ` [PATCH 08/25] Unionfs: lower nameidata support for nfsv4 Erez Zadok
2007-09-26 3:09 ` [PATCH 09/25] Unionfs: add un/likely conditionals on common fileops Erez Zadok
2007-09-26 3:09 ` [PATCH 10/25] Unionfs: add un/likely conditionals on copyup ops Erez Zadok
2007-09-26 4:32 ` Kok, Auke [this message]
2007-09-26 13:40 ` Erez Zadok
2007-09-26 15:23 ` Kyle Moffett
2007-09-26 15:43 ` Erez Zadok
2007-09-26 16:47 ` Jan Engelhardt
2007-09-26 16:51 ` Erez Zadok
2007-09-26 18:34 ` Adrian Bunk
2007-09-26 3:09 ` [PATCH 11/25] Unionfs: add un/likely conditionals on debug ops Erez Zadok
2007-09-26 21:34 ` roel
2007-09-26 3:09 ` [PATCH 12/25] Unionfs: add un/likely conditionals on dentry ops Erez Zadok
2007-09-26 3:09 ` [PATCH 13/25] Unionfs: add un/likely conditionals on dir ops Erez Zadok
2007-09-26 21:40 ` roel
2007-09-27 14:28 ` Erez Zadok
2007-09-26 3:09 ` [PATCH 14/25] Unionfs: add un/likely conditionals on headers Erez Zadok
2007-09-26 3:09 ` [PATCH 15/25] Unionfs: add un/likely conditionals on fileops Erez Zadok
2007-09-26 3:09 ` [PATCH 16/25] Unionfs: add un/likely conditionals on inode ops Erez Zadok
2007-09-26 3:09 ` [PATCH 17/25] Unionfs: add un/likely conditionals on lookup ops Erez Zadok
2007-09-26 3:09 ` [PATCH 18/25] Unionfs: add un/likely conditionals on super ops Erez Zadok
2007-09-26 3:09 ` [PATCH 19/25] Unionfs: add un/likely conditionals on mmap ops Erez Zadok
2007-09-26 3:09 ` [PATCH 20/25] Unionfs: add un/likely conditionals on rename ops Erez Zadok
2007-09-26 3:10 ` [PATCH 21/25] Unionfs: add un/likely conditionals on readdir ops Erez Zadok
2007-09-26 3:10 ` [PATCH 22/25] Unionfs: add un/likely conditionals on common subr Erez Zadok
2007-09-26 3:10 ` [PATCH 23/25] Unionfs: add un/likely conditionals on unlink ops Erez Zadok
2007-09-26 3:10 ` [PATCH 24/25] Unionfs: add un/likely conditionals on xattr ops Erez Zadok
2007-09-26 3:10 ` [PATCH 25/25] Unionfs: use poison.h for safe poison pointers Erez Zadok
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