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From: Jesse Brandeburg <jesse.brandeburg@intel.com>
To: Li RongQing <lirongqing@baidu.com>
Cc: <netdev@vger.kernel.org>, <intel-wired-lan@lists.osuosl.org>
Subject: Re: [PATCH][v3] i40e: optimise prefetch page refcount
Date: Tue, 18 Aug 2020 11:19:26 -0700	[thread overview]
Message-ID: <20200818111926.000028d9@intel.com> (raw)
In-Reply-To: <1597734477-27859-1-git-send-email-lirongqing@baidu.com>

On Tue, 18 Aug 2020 15:07:57 +0800
Li RongQing <lirongqing@baidu.com> wrote:

> refcount of rx_buffer page will be added here originally, so prefetchw
> is needed, but after commit 1793668c3b8c ("i40e/i40evf: Update code to
>  better handle incrementing page count"), and refcount is not added
> everytime, so change prefetchw as prefetch,
> 
> now it mainly services page_address(), but which accesses struct page
> only when WANT_PAGE_VIRTUAL or HASHED_PAGE_VIRTUAL is defined
> otherwise it returns address based on offset, so we prefetch it
> conditionally
> 
> Jakub suggested to define prefetch_page_address in a common header
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Li RongQing <lirongqing@baidu.com>

This change looks fine to me, hopefully the more heavyweight
prefetch instruction doesn't impact performance. Were you able to test
any performance?

Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>

WARNING: multiple messages have this Message-ID (diff)
From: Jesse Brandeburg <jesse.brandeburg@intel.com>
To: intel-wired-lan@osuosl.org
Subject: [Intel-wired-lan] [PATCH][v3] i40e: optimise prefetch page refcount
Date: Tue, 18 Aug 2020 11:19:26 -0700	[thread overview]
Message-ID: <20200818111926.000028d9@intel.com> (raw)
In-Reply-To: <1597734477-27859-1-git-send-email-lirongqing@baidu.com>

On Tue, 18 Aug 2020 15:07:57 +0800
Li RongQing <lirongqing@baidu.com> wrote:

> refcount of rx_buffer page will be added here originally, so prefetchw
> is needed, but after commit 1793668c3b8c ("i40e/i40evf: Update code to
>  better handle incrementing page count"), and refcount is not added
> everytime, so change prefetchw as prefetch,
> 
> now it mainly services page_address(), but which accesses struct page
> only when WANT_PAGE_VIRTUAL or HASHED_PAGE_VIRTUAL is defined
> otherwise it returns address based on offset, so we prefetch it
> conditionally
> 
> Jakub suggested to define prefetch_page_address in a common header
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Li RongQing <lirongqing@baidu.com>

This change looks fine to me, hopefully the more heavyweight
prefetch instruction doesn't impact performance. Were you able to test
any performance?

Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>

  reply	other threads:[~2020-08-18 18:19 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-18  7:07 [PATCH][v3] i40e: optimise prefetch page refcount Li RongQing
2020-08-18  7:07 ` [Intel-wired-lan] " Li RongQing
2020-08-18 18:19 ` Jesse Brandeburg [this message]
2020-08-18 18:19   ` Jesse Brandeburg
2020-09-04 23:45 ` Brown, Aaron F
2020-09-04 23:45   ` [Intel-wired-lan] " Brown, Aaron F

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