[Xen-devel] xen 2.0 testing idle_loop -and -03

[Adam Sulmicki <adam@xxxxxxxxxxxx>]

hello,
        I'm playing with xen 2.0 testing. I noticed few issues so far

1) extreme slowness
2) won't boot on p3 with compiled for for cyrix
3) "idle_loop" gets optimized away

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1) it is extremely slow. top shows that about 90% of time is spent in wait 
states (this is with compiling kernel)... seems like it might have been 
low memory situation.. but I did not have such problems with xen 2.0 
release.. (using dom0_mem=65536)
Cpu(s):  6.0% us,  1.6% sy,  0.0% ni,  0.0% id, 92.4% wa,  0.0% hi,  0.0% si

tops shows that 45mb out of 60mb are used but.. but it is nto clear what 
ofer.. it not programs, it does not seems like those are buffers either
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2) does not boot whith Processor family set to "cyrix III/VIA-C3"

(XEN) Scrubbing Free RAM: ..done.
(XEN) *** Serial input -> DOM0 (type 'CTRL-a' three times to switch input to 
Xen).
(XEN) BUG at domain.c:140
(XEN) CPU:    0
(XEN) EIP:    0808:[<fc505f9e>]
(XEN) EFLAGS: 00210296
(XEN) eax: 00000000   ebx: fc5fd9e0   ecx: 00200046   edx: 000003f8
(XEN) esi: 000e0002   edi: c0102000   ebp: 00000fc0   esp: fc503f9c
(XEN) ds: 0810   es: 0810   fs: 0810   gs: 0810   ss: 0810
(XEN) Stack trace from ESP=fc503f9c:
(XEN) fc52cd19 fc52cd5a 0000008c 000e0002 [fc505ec0] fc5fd9e0 000e0002 0000003f
(XEN) 00000517 00000000 c0512000 c0102000 00000fc0 c0464000 000e0000 00000000
(XEN) 00000819 00210246 c0000004 00000821 00000821 00000821 00000000 00000000
(XEN)        fc5fd9e0
(XEN) Call Trace from ESP=fc503f9c: [<fc505ec0>]

****************************************
CPU0 FATAL TRAP: vector = 6 (invalid operand)
[error_code=0000]
Aieee! CPU0 is toast...
****************************************

Reboot in five seconds...

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3) using -03 makes the "idle_loop" being optimized away.

removing the "-O3" flag while compiling the domain.o fixes the probelm.

['make xen' in today's bk pull of xen-2.0-testing.bk ..... ]

ld --oformat elf32-i386  -T x86_32/xen.lds -N \
    boot/x86_32.o /usr/src/cm/xen/xen-2.0-testing.bk/xen/common/common.o 
/usr/src/cm/xen/xen-2.0-testing.bk/xen/drivers/char/driver.o 
/usr/src/cm/xen/xen-2.0-testing.bk/xen/drivers/acpi/driver.o 
/usr/src/cm/xen/xen-2.0-testing.bk/xen/drivers/pci/driver.o 
/usr/src/cm/xen/xen-2.0-testing.bk/xen/arch/x86/arch.o -o 
/usr/src/cm/xen/xen-2.0-testing.bk/xen/xen-syms
/usr/src/cm/xen/xen-2.0-testing.bk/xen/arch/x86/arch.o(.text+0xa90): In 
function `continue_idle_task':
: undefined reference to `idle_loop'
make[2]: *** [default] Error 1
make[2]: Leaving directory `/usr/src/cm/xen/xen-2.0-testing.bk/xen/arch/x86'
make[1]: *** [/usr/src/cm/xen/xen-2.0-testing.bk/xen/xen] Error 2
make[1]: Leaving directory `/usr/src/cm/xen/xen-2.0-testing.bk/xen'
make: *** [xen] Error 2

redbull:/usr/src/cm/xen/xen-2.0-testing.bk #

redbull:/usr/src/cm/xen/xen-2.0-testing.bk # cd xen/arch/x86/

# compile with "-O3"

redbull:/usr/src/cm/xen/xen-2.0-testing.bk/xen/arch/x86 # gcc -nostdinc 
-fno-builtin -fno-common -fno-strict-aliasing -iwithprefix include -Wall 
-Werror -pipe -I/usr/src/cm/xen/xen-2.0-testing.bk/xen/include 
-Wno-pointer-arith -Wredundant-decls -O3 -fomit-frame-pointer -msoft-float 
-m32 -march=i586 -DNDEBUG -c domain.c -o domain.o
redbull:/usr/src/cm/xen/xen-2.0-testing.bk/xen/arch/x86 # gcc -nostdinc 
-fno-builtin -fno-common -fno-strict-aliasing -iwithprefix include -Wall 
-Werror -pipe -I/usr/src/cm/xen/xen-2.0-testing.bk/xen/include 
-Wno-pointer-arith -Wredundant-decls -O3 -fomit-frame-pointer -msoft-float 
-m32 -march=i586 -DNDEBUG -c domain.c -o domain.o
redbull:/usr/src/cm/xen/xen-2.0-testing.bk/xen/arch/x86 # nm domain.o | 
grep -iw idle_loop
         U idle_loop

# compile with-out "-O3"

redbull:/usr/src/cm/xen/xen-2.0-testing.bk/xen/arch/x86 # gcc -nostdinc 
-fno-builtin -fno-common -fno-strict-aliasing -iwithprefix include -Wall 
-Werror -pipe -I/usr/src/cm/xen/xen-2.0-testing.bk/xen/include 
-Wno-pointer-arith -Wredundant-decls -O0 -fomit-frame-pointer -msoft-float 
-m32 -march=i586 -DNDEBUG -c domain.c -o domain.o
redbull:/usr/src/cm/xen/xen-2.0-testing.bk/xen/arch/x86 # nm domain.o | 
grep -iw idle_loop
00000020 t idle_loop

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