I have a trouble with floating point number when I use xen. First I work on openSUSE 11.3, with xen-4.0.0_21091_05-6.6.x86_64. I create a windows XP domU, and make a simple program dealing with floating point number by Visual C++ 6. The program is: void BUG() { while(1); } func() { float f = 1; while(1) { TRACE(f = %f\n, f); if(f < 0) BUG(); Sleep(1000); } } When I use xm migrate live win1 hosta, (hosta is the same computer), sometime print f = -1.#IND0, sometime goto BUG(). Why()? Then I use xen-4.0.1-rc6, the same thing happen. Is this a BUG of xen? My CPU is Intel Xeon L5408.When I use other CPU, for example Xeon L5420,I rarely meet the problem. 2010-09-06 ywzheng _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Pasi Kärkkäinen
2010-Sep-06 09:07 UTC
Re: [Xen-devel] xen trouble while guest excute float app
On Mon, Sep 06, 2010 at 09:51:42AM +0800, ywzheng wrote:> I have a trouble with floating point number when I use xen. First I work > on openSUSE 11.3, with xen-4.0.0_21091_05-6.6.x86_64. I create a windows > XP domU, and make a simple program dealing with floating point number by > Visual C++ 6. The program is: > > void BUG() > > { > > while(1); > > } > > func() > > { > > float f = 1; > > > > while(1) > > { > > TRACE("f = %f\n", f); > > if(f < 0) > > BUG(); > > Sleep(1000); > > } > > } > > > > When I use "xm migrate -live win1 hosta", (hosta is the same computer), > sometime print f = -1.#IND0, sometime goto BUG(). Why()? > > > > Then I use xen-4.0.1-rc6, the same thing happen. Is this a BUG of xen? > > My CPU is Intel Xeon L5408.When I use other CPU, for example Xeon L5420,I > rarely meet the problem. > >Hello, Interesting problem.. Did you try just save/restore of the VM? Does it show the same issue? Or is it only during live migration? -- Pasi _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
At 02:51 +0100 on 06 Sep (1283741502), ywzheng wrote:> When I use ?xm migrate ?live win1 hosta?, (hosta is the same computer), sometime print f = -1.#IND0, sometime goto BUG(). Why()? > > Then I use xen-4.0.1-rc6, the same thing happen. Is this a BUG of xen?Yes, this bug was introduced by Intel''s patches to support XSAVE, which broke save/restore. Unfortunately it was only fixed very recently so it''s not fixed in 4.0.1; you''ll need the very latest 4.0-testing Xen. Cheers, Tim.> My CPU is Intel Xeon L5408.When I use other CPU, for example Xeon L5420,I rarely meet the problem. > > 2010-09-06 > ________________________________ > ywzheng-- Tim Deegan <Tim.Deegan@citrix.com> Principal Software Engineer, XenServer Engineering Citrix Systems UK Ltd. (Company #02937203, SL9 0BG) _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Pasi Kärkkäinen
2010-Sep-06 10:47 UTC
Re: [Xen-devel] xen trouble while guest excute float app
On Mon, Sep 06, 2010 at 11:32:54AM +0100, Tim Deegan wrote:> At 02:51 +0100 on 06 Sep (1283741502), ywzheng wrote: > > When I use ?xm migrate ?live win1 hosta?, (hosta is the same computer), sometime print f = -1.#IND0, sometime goto BUG(). Why()? > > > > Then I use xen-4.0.1-rc6, the same thing happen. Is this a BUG of xen? > > Yes, this bug was introduced by Intel''s patches to support XSAVE, which > broke save/restore. Unfortunately it was only fixed very recently so > it''s not fixed in 4.0.1; you''ll need the very latest 4.0-testing Xen. >Ok, so it''s fixed in here: http://xenbits.xen.org/xen-4.0-testing.hg "5 days ago: x86 intel: Disable XSAVE support." -- Pasi _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2010-Sep-06 11:54 UTC
Re: [Xen-devel] xen trouble while guest excute float app
On 06/09/2010 03:32, "Tim Deegan" <Tim.Deegan@citrix.com> wrote:> At 02:51 +0100 on 06 Sep (1283741502), ywzheng wrote: >> When I use ?xm migrate ?live win1 hosta?, (hosta is the same computer), >> sometime print f = -1.#IND0, sometime goto BUG(). Why()? >> >> Then I use xen-4.0.1-rc6, the same thing happen. Is this a BUG of xen? > > Yes, this bug was introduced by Intel''s patches to support XSAVE, which > broke save/restore. Unfortunately it was only fixed very recently so > it''s not fixed in 4.0.1; you''ll need the very latest 4.0-testing Xen.Or you can just add no-xsave to the Xen command line.> Cheers, > > Tim. > >> My CPU is Intel Xeon L5408.When I use other CPU, for example Xeon L5420,I >> rarely meet the problem. >> >> 2010-09-06 >> ________________________________ >> ywzheng_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
ywzheng
2010-Sep-06 12:32 UTC
Re: Re: [Xen-devel] xen trouble while guest excute float app
Thanks I will try it. 2010-09-06 ywzheng 发件人: Pasi K鋜kk鋓nen 发送时间: 2010-09-06 18:48:00 收件人: Tim Deegan 抄送: ywzheng; xen-devel 主题: Re: [Xen-devel] xen trouble while guest excute float app On Mon, Sep 06, 2010 at 11:32:54AM +0100, Tim Deegan wrote:> At 02:51 +0100 on 06 Sep (1283741502), ywzheng wrote: > > When I use ?xm migrate ?live win1 hosta?, (hosta is the same computer), sometime print f = -1.#IND0, sometime goto BUG(). Why()? > > > > Then I use xen-4.0.1-rc6, the same thing happen. Is this a BUG of xen? > > Yes, this bug was introduced by Intel's patches to support XSAVE, which > broke save/restore. Unfortunately it was only fixed very recently so > it's not fixed in 4.0.1; you'll need the very latest 4.0-testing Xen. >Ok, so it's fixed in here: http://xenbits.xen.org/xen-4.0-testing.hg "5 days ago: x86 intel: Disable XSAVE support." -- Pasi _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel