From: Ian Campbell <Ian.Campbell@citrix.com>
To: Tamas K Lengyel <tamas.lengyel@zentific.com>
Cc: wei.liu2@citrix.com, Tim Deegan <tim@xen.org>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
Stefano Stabellini <stefano.stabellini@citrix.com>,
Daniel De Graaf <dgdegra@tycho.nsa.gov>
Subject: Re: [PATCH for-4.5 v11 0/9] Mem_event and mem_access for ARM
Date: Mon, 29 Sep 2014 16:21:36 +0100 [thread overview]
Message-ID: <1412004096.3801.28.camel@citrix.com> (raw)
In-Reply-To: <CAErYnsia_d9W_aeE6jfVnmAJf9QuF_hNdKEeToWnvbPcQ-_GfQ@mail.gmail.com>
On Mon, 2014-09-29 at 17:17 +0200, Tamas K Lengyel wrote:
>
> For example I think they would would have pretty clearly shown
> poor
> performance due to the copy to/from user changes in your
> previous
> iteration.
>
> Ian.
>
>
> You are probably right, but aren't the copy to/from helpers only used
> if the guest is issuing hypercalls? I mean, what would the hypervisor
> copy in/out of the guest during kernbench running in the guest? That
> doesn't really sound right to me.
Guests (and dom0 issue hypercalls as part of the PV ring protocols
(kicking evtchns, mapping and unmapping grant references, etc) and for a
variety of other things while they are running workloads. For almost all
of those operations some sort of argument struct normally needs to be
copied in/out (often both) of guest memory.
Ian.
next prev parent reply other threads:[~2014-09-29 15:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-29 11:36 [PATCH for-4.5 v11 0/9] Mem_event and mem_access for ARM Tamas K Lengyel
2014-09-29 11:36 ` [PATCH for-4.5 v11 1/9] xen/arm: p2m changes for mem_access support Tamas K Lengyel
2014-09-29 12:26 ` Julien Grall
2014-09-29 12:41 ` Tamas K Lengyel
2014-09-29 11:36 ` [PATCH for-4.5 v11 2/9] xen/arm: Implement domain_get_maximum_gpfn Tamas K Lengyel
2014-09-29 11:36 ` [PATCH for-4.5 v11 3/9] xen/arm: Add p2m_set_permission and p2m_shatter_page helpers Tamas K Lengyel
2014-09-29 11:36 ` [PATCH for-4.5 v11 4/9] xen/arm: Data abort exception (R/W) mem_events Tamas K Lengyel
2014-09-29 12:35 ` Julien Grall
2014-09-29 12:47 ` Tamas K Lengyel
2014-09-29 12:52 ` Julien Grall
2014-09-29 12:53 ` Julien Grall
2014-09-29 11:36 ` [PATCH for-4.5 v11 5/9] xen/arm: Allow hypervisor access to mem_access protected pages Tamas K Lengyel
2014-09-29 14:12 ` Julien Grall
2014-09-29 14:44 ` Tamas K Lengyel
2014-09-29 14:50 ` Julien Grall
2014-09-29 14:57 ` Tamas K Lengyel
2014-09-29 15:07 ` Julien Grall
2014-09-29 11:36 ` [PATCH for-4.5 v11 6/9] xen/arm: Instruction prefetch abort (X) mem_event handling Tamas K Lengyel
2014-09-29 14:13 ` Julien Grall
2014-09-29 11:36 ` [PATCH for-4.5 v11 7/9] xen/arm: Enable the compilation of mem_access and mem_event on ARM Tamas K Lengyel
2014-09-29 11:36 ` [PATCH for-4.5 v11 8/9] tools/libxc: Allocate magic page for mem access " Tamas K Lengyel
2014-09-29 11:36 ` [PATCH for-4.5 v11 9/9] tools/tests: Enable xen-access " Tamas K Lengyel
2014-09-29 14:16 ` Julien Grall
2014-09-29 12:17 ` [PATCH for-4.5 v11 0/9] Mem_event and mem_access for ARM Tamas K Lengyel
2014-09-29 13:37 ` Ian Campbell
2014-09-29 14:21 ` Tamas K Lengyel
2014-09-29 15:07 ` Ian Campbell
2014-09-29 15:17 ` Tamas K Lengyel
2014-09-29 15:21 ` Ian Campbell [this message]
2014-09-29 15:29 ` Tamas K Lengyel
2014-09-30 11:02 ` Stefano Stabellini
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