Re: kvm-s390: Dont exit SIE on SIGP sense running

2010-06-21 Thread Avi Kivity 

On 06/18/2010 12:16 AM, Christian Borntraeger wrote:

Avi, Marcello,

Newer (guest) kernels use sigp sense running in their spinlock
implementation to check if the other cpu is running before yielding
the processor. This revealed some wrong guest settings, causing
unnecessary exits for every sigp sense running.
   


Applied, thanks.


  void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
  {
VCPU_EVENT(vcpu, 3, %s, free cpu);
+   clear_bit(63 - vcpu-vcpu_id, (unsigned long 
*)vcpu-kvm-arch.sca-mcn);
if (vcpu-kvm-arch.sca-cpu[vcpu-vcpu_id].sda ==
(__u64) vcpu-arch.sie_block)
vcpu-kvm-arch.sca-cpu[vcpu-vcpu_id].sda = 0;
   


Unrelated, do these VCPU_EVENTs want to become ftrace tracepoints?

--
error compiling committee.c: too many arguments to function

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Re: kvm-s390: Dont exit SIE on SIGP sense running

2010-06-21 Thread Christian Borntraeger 
Am Montag 21 Juni 2010, 10:27:50 schrieb Avi Kivity:
[...]
  VCPU_EVENT(vcpu, 3, %s, free cpu);
  +   clear_bit(63 - vcpu-vcpu_id, (unsigned long 
  *)vcpu-kvm-arch.sca-mcn);
  if (vcpu-kvm-arch.sca-cpu[vcpu-vcpu_id].sda ==
  (__u64) vcpu-arch.sie_block)
  vcpu-kvm-arch.sca-cpu[vcpu-vcpu_id].sda = 0;
 
 
 Unrelated, do these VCPU_EVENTs want to become ftrace tracepoints?
 
 

Hmm, dont know. Currently this calls into a s390 debug tracing facility
(arch/s390/kernel/debug.c) which is heavily used by our service folks.
There are commands for crash and lcrash to show these s390 debug traces
from a dump.

Maybe its worth to investigate if we should change some of these events to
have both ftrace-tracepoints and the debug traces.

Christian
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Re: kvm-s390: Dont exit SIE on SIGP sense running

2010-06-21 Thread Arnd Bergmann 
On Monday 21 June 2010, Christian Borntraeger wrote:
 Hmm, dont know. Currently this calls into a s390 debug tracing facility
 (arch/s390/kernel/debug.c) which is heavily used by our service folks.
 There are commands for crash and lcrash to show these s390 debug traces
 from a dump.
 
 Maybe its worth to investigate if we should change some of these events to
 have both ftrace-tracepoints and the debug traces.

I think that it would be worthwhile to convert the entire s390 debug
code to become tracepoints, either one by one or making it a subclass
with the existing interfaces.

Arnd
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kvm-s390: Dont exit SIE on SIGP sense running

2010-06-17 Thread Christian Borntraeger 
Avi, Marcello,

Newer (guest) kernels use sigp sense running in their spinlock
implementation to check if the other cpu is running before yielding
the processor. This revealed some wrong guest settings, causing
unnecessary exits for every sigp sense running.
 
Signed-off-by: Christian Borntraeger borntrae...@de.ibm.com

---
 arch/s390/include/asm/kvm_host.h |2 +-
 arch/s390/kvm/kvm-s390.c |4 +++-
 2 files changed, 4 insertions(+), 2 deletions(-)

Index: kvm/arch/s390/include/asm/kvm_host.h
===
--- kvm.orig/arch/s390/include/asm/kvm_host.h
+++ kvm/arch/s390/include/asm/kvm_host.h
@@ -26,7 +26,7 @@
 
 struct sca_entry {
atomic_t scn;
-   __u64   reserved;
+   __u32   reserved;
__u64   sda;
__u64   reserved2[2];
 } __attribute__((packed));
Index: kvm/arch/s390/kvm/kvm-s390.c
===
--- kvm.orig/arch/s390/kvm/kvm-s390.c
+++ kvm/arch/s390/kvm/kvm-s390.c
@@ -207,6 +207,7 @@ out_nokvm:
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
VCPU_EVENT(vcpu, 3, %s, free cpu);
+   clear_bit(63 - vcpu-vcpu_id, (unsigned long *) 
vcpu-kvm-arch.sca-mcn);
if (vcpu-kvm-arch.sca-cpu[vcpu-vcpu_id].sda ==
(__u64) vcpu-arch.sie_block)
vcpu-kvm-arch.sca-cpu[vcpu-vcpu_id].sda = 0;
@@ -296,7 +297,7 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu 
 {
atomic_set(vcpu-arch.sie_block-cpuflags, CPUSTAT_ZARCH);
set_bit(KVM_REQ_MMU_RELOAD, vcpu-requests);
-   vcpu-arch.sie_block-ecb   = 2;
+   vcpu-arch.sie_block-ecb   = 6;
vcpu-arch.sie_block-eca   = 0xC1002001U;
vcpu-arch.sie_block-fac   = (int) (long) facilities;
hrtimer_init(vcpu-arch.ckc_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
@@ -329,6 +330,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(st
kvm-arch.sca-cpu[id].sda = (__u64) vcpu-arch.sie_block;
vcpu-arch.sie_block-scaoh = (__u32)(((__u64)kvm-arch.sca)  32);
vcpu-arch.sie_block-scaol = (__u32)(__u64)kvm-arch.sca;
+   set_bit(63 - id, (unsigned long *) kvm-arch.sca-mcn);
 
spin_lock_init(vcpu-arch.local_int.lock);
INIT_LIST_HEAD(vcpu-arch.local_int.list);
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