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From: Anthony Liguori <anthony-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>
To: Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
Cc: kvm-devel
	<kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>,
	lguest <lguest-mnsaURCQ41sdnm+yROfE0A@public.gmane.org>,
	virtualization-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
Subject: Re: [kvm-devel] [RFC PATCH 1/5] lguest: mmap backing file
Date: Thu, 20 Mar 2008 09:04:17 -0500	[thread overview]
Message-ID: <47E26EE1.5030706@codemonkey.ws> (raw)
In-Reply-To: <200803201705.44422.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>

Rusty Russell wrote:
> From: Paul TBBle Hampson <Paul.Hampson-vM6MUUi4OUAAvxtiuMwx3w@public.gmane.org>
>
> This creates a file in $HOME/.lguest/ to directly back the RAM and DMA memory
> mappings created by map_zeroed_pages.
>   

I created a test program recently that measured the latency of a 
reads/writes to an mmap() file in /dev/shm and in a normal filesystem.  
Even after unlinking the underlying file, the write latency was much 
better with a mmap()'d file in /dev/shm.

/dev/shm is not really for general use.  I think we'll want to have our 
own tmpfs mount that we use to create VM images.  I also prefer to use a 
unix socket for communication, unlink the file immediately after open, 
and then pass the fd via SCM_RIGHTS to the other process.

Regards,

Anthony Liguori

  parent reply	other threads:[~2008-03-20 14:04 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-20  5:59 [RFC PATCH 0/4] Inter-guest virtio I/O example with lguest Rusty Russell
     [not found] ` <200803201659.14344.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2008-03-20  6:05   ` [RFC PATCH 1/5] lguest: mmap backing file Rusty Russell
2008-03-20  8:16     ` [Lguest] " Tim Post
     [not found]       ` <1206000960.6873.124.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2008-03-20 14:07         ` Paul TBBle Hampson
2008-03-21  0:29         ` Rusty Russell
     [not found]     ` <200803201705.44422.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2008-03-20  6:22       ` [RFC PATCH 2/5] lguest: Encapsulate Guest memory ready for dealing with other Guests Rusty Russell
2008-03-20  6:36         ` [RFC PATCH 3/5] lguest: separate out virtqueue info from device info Rusty Russell
     [not found]           ` <200803201736.01883.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2008-03-20  6:40             ` [RFC PATCH 4/5] lguest: ignore bad virtqueues Rusty Russell
2008-03-20  6:45               ` [RFC PATCH 5/5] lguest: Inter-guest networking Rusty Russell
2008-03-20 14:04       ` Anthony Liguori [this message]
     [not found]         ` <47E26EE1.5030706-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>
2008-03-20 14:32           ` [kvm-devel] [RFC PATCH 1/5] lguest: mmap backing file Paul TBBle Hampson
2008-03-20 15:07           ` Avi Kivity
2008-03-20 15:24             ` Anthony Liguori
2008-03-20 22:12           ` [kvm-devel] " Rusty Russell
2008-03-20 23:46             ` Anthony Liguori
2008-03-23  9:11               ` Avi Kivity
2008-03-20  6:54   ` [kvm-devel] [RFC PATCH 0/4] Inter-guest virtio I/O example with lguest Avi Kivity
     [not found]     ` <47E20A35.2000600-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2008-03-20 13:55       ` Anthony Liguori
     [not found]         ` <47E26CC1.8080900-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>
2008-03-20 14:27           ` Avi Kivity
     [not found]             ` <47E27461.4090404-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2008-03-20 14:39               ` Anthony Liguori
2008-03-20 14:55                 ` Avi Kivity
2008-03-20 15:05                   ` Anthony Liguori
2008-03-20 15:36                     ` Avi Kivity
     [not found]                       ` <47E28482.9010501-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2008-03-20 15:52                         ` [kvm-devel] " Anthony Liguori
2008-03-20 22:14     ` Rusty Russell
2008-03-20 14:11   ` [kvm-devel] " Anthony Liguori
2008-03-23 12:05     ` Rusty Russell

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