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From: Yann Droneaud <ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>
To: Sagi Grimberg
	<sagig-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>,
	Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Matan Barak <matanb-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
	Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Subject: Re: [PATCH] IB/mlx5: Reduce mlx5_ib_wq cacheline bouncing
Date: Wed, 13 Jan 2016 10:26:34 +0100	[thread overview]
Message-ID: <1452677194.9500.27.camel@opteya.com> (raw)
In-Reply-To: <56960E5C.5000607-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>

Le mercredi 13 janvier 2016 à 10:44 +0200, Sagi Grimberg a écrit :
> > Anyway, I'm not sure about the alignment of the memory returned by
> > kcalloc(), I should have known by the time but don't find time to
> > figure how it's handled on various SL*B allocator implementation.
> 
> Can you explain why should I worry about the alignment of kcalloc
> here?

Say it returns memory aligned on 16 bytes, then accessing some items in
the array is going to touch 2 cachelines, defeating the purpose of the
padding or the alignment attribute added to the item structure.

Regards.

-- 
Yann Droneaud
OPTEYA

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  parent reply	other threads:[~2016-01-13  9:26 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-12 10:32 [PATCH] IB/mlx5: Reduce mlx5_ib_wq cacheline bouncing Sagi Grimberg
     [not found] ` <1452594732-9573-1-git-send-email-sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2016-01-12 12:16   ` Or Gerlitz
     [not found]     ` <5694EEAA.3050600-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2016-01-12 14:44       ` Sagi Grimberg
     [not found]         ` <56951130.60802-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2016-01-12 14:53           ` Or Gerlitz
     [not found]             ` <56951375.1050704-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2016-01-12 14:58               ` Sagi Grimberg
     [not found]                 ` <569514A5.1050705-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2016-01-12 15:05                   ` Or Gerlitz
     [not found]                     ` <56951634.5030307-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2016-01-12 15:09                       ` Sagi Grimberg
2016-01-13  8:55                   ` Or Gerlitz
2016-01-12 14:37   ` Yann Droneaud
     [not found]     ` <1452609431.9500.24.camel-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>
2016-01-13  8:44       ` Sagi Grimberg
     [not found]         ` <56960E5C.5000607-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2016-01-13  9:26           ` Yann Droneaud [this message]
     [not found]             ` <1452677194.9500.27.camel-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>
2016-01-13  9:37               ` Sagi Grimberg

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