From: David Sterba <dsterba@suse.cz>
To: kernel test robot <oliver.sang@intel.com>
Cc: Qu Wenruo <wqu@suse.com>,
oe-lkp@lists.linux.dev, lkp@intel.com,
Linux Memory Management List <linux-mm@kvack.org>,
David Sterba <dsterba@suse.com>,
linux-btrfs@vger.kernel.org, ying.huang@intel.com,
feng.tang@intel.com, fengwei.yin@intel.com
Subject: Re: [linux-next:master] [btrfs] 8d99361835: stress-ng.link.ops_per_sec -18.0% regression
Date: Tue, 2 Jan 2024 17:26:20 +0100 [thread overview]
Message-ID: <20240102162620.GA15380@twin.jikos.cz> (raw)
In-Reply-To: <202312221750.571925bd-oliver.sang@intel.com>
On Fri, Dec 22, 2023 at 05:59:34PM +0800, kernel test robot wrote:
>
>
> Hello,
>
> kernel test robot noticed a -18.0% regression of stress-ng.link.ops_per_sec on:
>
>
> commit: 8d993618350c86da11cb408ba529c13e83d09527 ("btrfs: migrate get_eb_page_index() and get_eb_offset_in_page() to folios")
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
Unfortunatelly the conversion to folios adds a lot of assembly code and
we can't rely on constants like PAGE_SIZE anymore. The calculations in
extent buffer members are therefore slower, 18% is a lot but within my
expected range for metadta-only operations.
This could be improved by caching some values, like folio_size, so it's
a dereference and not a calculation of "PAGE_SIZE << folio_order" with
conditionals around.
next prev parent reply other threads:[~2024-01-02 16:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-22 9:59 kernel test robot
2024-01-02 16:26 ` David Sterba [this message]
2024-01-02 21:02 ` Qu Wenruo
2024-01-02 22:18 ` Matthew Wilcox
2024-01-02 22:32 ` Qu Wenruo
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