RE: [Xen-ia64-devel] [PATCH] This is the first patch to merge vcpu.c

["Xu, Anthony" <anthony.xu@xxxxxxxxx>]

Dan,

The test is on latest xen0 without my patch.
So what can I do now?

Thanks
Anthony


>-----Original Message-----
>From: Magenheimer, Dan (HP Labs Fort Collins) [mailto:dan.magenheimer@xxxxxx]
>Sent: 2005年9月16日 21:04
>To: Xu, Anthony
>Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>Subject: RE: [Xen-ia64-devel] [PATCH] This is the first patch to merge vcpu.c
>
>I guess the next step is to remove your entire patch and
>rerun the test to see if the problem goes away (as it
>does for me).  You may see about 1 out of 10 linux-builds
>fail with a segmentation violation; this needs to be tracked
>down (with a hardware debugger)... it was a regression that
>I started seeing in July (when the first merge, vcpu_translate,
>and some of the fast paths went in... I turned off the fast
>paths and the problem didn't go away and haven't looked
>at it since).
>
>If the infinite loop problem goes away with no patch, try
>breaking up your patch into multiple patches and see which
>one provokes the problem.  If you are good with scripting
>(I'm not!), you might be able to catch it earlier with a script
>that runs "ps" and notices if any task has used more than a
>minute of CPU time.
>
>Dan
>
>> -----Original Message-----
>> From: Xu, Anthony [mailto:anthony.xu@xxxxxxxxx]
>> Sent: Friday, September 16, 2005 5:12 AM
>> To: Xu, Anthony; Magenheimer, Dan (HP Labs Fort Collins)
>> Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> Subject: RE: [Xen-ia64-devel] [PATCH] This is the first patch
>> to merge vcpu.c
>>
>> Dan,
>> I am testing the latest xenolinux using your script,
>> The first three times of building kernel is successful.
>> At the fourth time, gcc seems has frozen or gotten into an
>> infinite loop, and not make forward progress, just like what you saw,
>> My platform is tiger4 with Madison.
>>
>> Thanks
>> Anthony
>>
>> -----Original Message-----
>> >From: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
>> >[mailto:xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx] On
>> Behalf Of Xu, Anthony
>> >Sent: 2005年9月16日 11:53
>> >To: Magenheimer, Dan (HP Labs Fort Collins)
>> >Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >Subject: RE: [Xen-ia64-devel] [PATCH] This is the first
>> patch to merge vcpu.c
>> >
>> >Dan,
>> >
>> >The build-test is very slow; I am testing the latest
>> xenolinux using your script,
>> >It cost 3 hours for 4 times of building.
>> >
>> >Thanks
>> >Anthony
>> >
>> >>-----Original Message-----
>> >>From: Magenheimer, Dan (HP Labs Fort Collins)
>> [mailto:dan.magenheimer@xxxxxx]
>> >>Sent: 2005年9月15日 11:53
>> >>To: Xu, Anthony
>> >>Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >>Subject: RE: [Xen-ia64-devel] [PATCH] This is the first
>> patch to merge vcpu.c
>> >>
>> >>Script attached.  It's not pretty and will need
>> >>to be adapted for a different environment, but
>> >>I've used the same script for a long time so
>> >>that I can compare results.
>> >>
>> >>The privcnt lines can be removed... I can't find
>> >>the source for privcnt, but it is probably the
>> >>same as what I posted here:
>> >>
>> >>http://lists.xensource.com/archives/html/xen-devel/2005-03/m
>sg00216.html
>> >>
>> >>> -----Original Message-----
>> >>> From: Xu, Anthony [mailto:anthony.xu@xxxxxxxxx]
>> >>> Sent: Wednesday, September 14, 2005 8:38 PM
>> >>> To: Magenheimer, Dan (HP Labs Fort Collins)
>> >>> Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >>> Subject: RE: [Xen-ia64-devel] [PATCH] This is the first patch
>> >>> to merge vcpu.c
>> >>>
>> >>> Thanks for your suggestion,
>> >>> Please send me your buildlinux script, see whether I can
>> reproduce it.
>> >>> And I can do this stress_test before I send patch..
>> >>>
>> >>> Thanks
>> >>> Anthony
>> >>>
>> >>>
>> >>>
>> >>> >-----Original Message-----
>> >>> >From: Magenheimer, Dan (HP Labs Fort Collins)
>> >>> [mailto:dan.magenheimer@xxxxxx]
>> >>> >Sent: 2005年9月15日 10:18
>> >>> >To: Xu, Anthony
>> >>> >Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >>> >Subject: RE: [Xen-ia64-devel] [PATCH] This is the first
>> >>> patch to merge vcpu.c
>> >>> >
>> >>> >I forgot to add: This kind of bug is VERY difficult to
>> >>> >find and fix because there is no obvious trigger to
>> >>> >start debugging.  With the segmentation fault, the
>> >>> >delivery of a fault is rare enough that one can
>> >>> >add code to the hypervisor to printf info when it
>> >>> >happens, but if a user app (especially something
>> >>> >as large and complex as a compiler) just goes into
>> >>> >an infinite loop, there's nothing as a trigger.
>> >>> >
>> >>> >If you can reproduce this, I'd suggest breaking
>> >>> >down the patch into smaller patches to see what
>> >>> >specific change causes the problem.  If I just
>> >>> >accept the patch, it will be much harder to track
>> >>> >the problem down later.
>> >>> >
>> >>> >> -----Original Message-----
>> >>> >> From: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
>> >>> >> [mailto:xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf
>> >>> >> Of Magenheimer, Dan (HP Labs Fort Collins)
>> >>> >> Sent: Wednesday, September 14, 2005 8:09 PM
>> >>> >> To: Xu, Anthony
>> >>> >> Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >>> >> Subject: RE: [Xen-ia64-devel] [PATCH] This is the first patch
>> >>> >> to merge vcpu.c
>> >>> >>
>> >>> >> Yes, definitely, I run my stress test before checking
>> >>> >> in any change.  I do periodically see a segmentation
>> >>> >> fault (ever since about mid-July when the first round
>> >>> >> of merge changes went in) that I haven't been able
>> >>> >> to isolate yet, but have never seen this "freeze"
>> >>> >> behavior before.
>> >>> >>
>> >>> >> > -----Original Message-----
>> >>> >> > From: Xu, Anthony [mailto:anthony.xu@xxxxxxxxx]
>> >>> >> > Sent: Wednesday, September 14, 2005 7:03 PM
>> >>> >> > To: Magenheimer, Dan (HP Labs Fort Collins)
>> >>> >> > Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >>> >> > Subject: RE: [Xen-ia64-devel] [PATCH] This is the first patch
>> >>> >> > to merge vcpu.c
>> >>> >> >
>> >>> >> > Hi Dan,
>> >>> >> >
>> >>> >> > I haven't stress-tested my patch, my patch almost doesn't
>> >>> >> > touch xeno code,
>> >>> >> > I am curious have you done the same stress-test on dom0
>> >>> >> > without my patch?
>> >>> >> > I think we'd better setup the infrastructure ( domU and VTdom
>> >>> >> > up) first, then we will come back to make all this stable.
>> >>> >> >
>> >>> >> > Thanks
>> >>> >> > Anthony
>> >>> >> >
>> >>> >> > >-----Original Message-----
>> >>> >> > >From: Magenheimer, Dan (HP Labs Fort Collins)
>> >>> >> > [mailto:dan.magenheimer@xxxxxx]
>> >>> >> > >Sent: 2005年9月14日 12:48
>> >>> >> > >To: Xu, Anthony
>> >>> >> > >Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >>> >> > >Subject: RE: [Xen-ia64-devel] [PATCH] This is the first
>> >>> >> > patch to merge vcpu.c
>> >>> >> > >
>> >>> >> > >Hi Anthony --
>> >>> >> > >
>> >>> >> > >I tried your patch.  It applies cleanly and compiles
>> >>> >> > >cleanly.  However, I am seeing problems when testing it.
>> >>> >> > >I run a script that builds linux ten times as
>> >>> >> > >a stress test.  During this test, twice, gcc has
>> >>> >> > >frozen or gotten into an infinite loop; I'm not
>> >>> >> > >really sure other than it continues to eat up CPU
>> >>> >> > >time and not make forward progress.  Other times
>> >>> >> > >building linux completes OK.
>> >>> >> > >
>> >>> >> > >Have you stress-tested the patch on your system?
>> >>> >> > >I would be curious whether you can reproduce it.
>> >>> >> > >I can send you my buildlinux script if you like.
>> >>> >> > >
>> >>> >> > >Dan
>> >>> >> > >
>> >>> >> > >
>> >>> >> > >> -----Original Message-----
>> >>> >> > >> From: Xu, Anthony [mailto:anthony.xu@xxxxxxxxx]
>> >>> >> > >> Sent: Monday, September 12, 2005 6:28 AM
>> >>> >> > >> To: Magenheimer, Dan (HP Labs Fort Collins)
>> >>> >> > >> Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >>> >> > >> Subject: [Xen-ia64-devel] [PATCH] This is the
>> first patch to
>> >>> >> > >> merge vcpu.c
>> >>> >> > >>
>> >>> >> > >> Dan,
>> >>> >> > >> This patch is based on ver 6723. And definitely I can boot
>> >>> >> > >> dom0 with this patch.
>> >>> >> > >>
>> >>> >> > >> Following things are done in this patch.
>> >>> >> > >> 1. Merge structure pt_reg.
>> >>> >> > >> 2. Though vcpu_info structure has been merged,
>> non-vt domain
>> >>> >> > >> used pointer vcpu->vcpu_info->arch.privregs, and vt domain
>> >>> >> > >> used pointer vcpu->arch.arch_vmx.vpd, the value
>> of these two
>> >>> >> > >> pointers are different, that means vt and non-vt
>> domain still
>> >>> >> > >> use different privileged registers pages, in this case, we
>> >>> >> > >> can't merge vcpu.c, so I merged these two
>> pointer, and put it
>> >>> >> > >> at vcpu->arch.privregs. vcpu->vcpu_info->arch.privregs and
>> >>> >> > >> vcpu->arch.arch_vmx.vpd  will not exist. Why put it at
>> >>> >> > >> vcpu->arch.privregs?  1. There will be one less pointer
>> >>> >> > >> unreferenced when accessing this privileged
>> registers page.
>> >>> >> > >> 2. vcpu->vcpu_info can be accessed by guest, but
>> guest can't
>> >>> >> > >> access privileged registers page through this
>> address, guest
>> >>> >> > >> can access this privileged page only through
>> another special
>> >>> >> > >> mapping. So there is no need to expose this
>> pointer to guest
>> >>> >> > >> by putting it in vcpu->vcpu_info structure. All
>> accesses to
>> >>> >> > >> this page is through VCPU(vcpu,y) macro,
>> >>> >> > >> 3. Merged following functions.
>> >>> >> > >>  Vcpu_set/get_(interruption control registers from cr16
>> >>> >> > >> to cr25), corresponding functions vmx_vcpu_set/get_***
>> >>> >> > will not exist.
>> >>> >> > >>  Vcpu->arch.arch_vmx.in_service[4] will not exist, we
>> >>> >> > >> will all use vcpu->arch.insvc[4]
>> >>> >> > >> 4. Cleaned up some unused structure members and codes.
>> >>> >> > >>
>> >>> >> > >>
>> >>> >> > >> Signed-off-by Anthony Xu <Anthony.xu@xxxxxxxxx>
>> >>> >> > >>
>> >>> >> > >> Thanks,
>> >>> >> > >> Anthony
>> >>> >> > >>
>> >>> >> >
>> >>> >>
>> >>>
>> >
>> >_______________________________________________
>> >Xen-ia64-devel mailing list
>> >Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>> >http://lists.xensource.com/xen-ia64-devel
>>

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