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[Qemu-devel] [PATCH for-2.8 04/38] s390/sclp: cache the sclp device
From: |
Cornelia Huck |
Subject: |
[Qemu-devel] [PATCH for-2.8 04/38] s390/sclp: cache the sclp device |
Date: |
Mon, 29 Aug 2016 13:44:56 +0200 |
From: Christian Borntraeger <address@hidden>
With the current code a simple sclp command takes about 13000 ns
The biggest part seems to be the resolver of the object model. By
caching the sclp device the time for an sclp command goes down to
2500ns. Talking about real life scenarios, this change doubles
the speed of the sclp console when sending single bytes outputs
to /dev/console.
Signed-off-by: Christian Borntraeger <address@hidden>
Reviewed-by: Cornelia Huck <address@hidden>
Signed-off-by: Cornelia Huck <address@hidden>
---
hw/s390x/sclp.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index fca37f5..540226c 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -26,7 +26,12 @@
static inline SCLPDevice *get_sclp_device(void)
{
- return SCLP(object_resolve_path_type("", TYPE_SCLP, NULL));
+ static SCLPDevice *sclp;
+
+ if (!sclp) {
+ sclp = SCLP(object_resolve_path_type("", TYPE_SCLP, NULL));
+ }
+ return sclp;
}
/* Provide information about the configuration, CPUs and storage */
--
2.9.3
- [Qemu-devel] [PATCH for-2.8 00/38] s390x patches for 2.8, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 03/38] s390x/pci: assert zpci always existing, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 10/38] qmp: details about CPU definitions in query-cpu-definitions, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 23/38] s390x/sclp: introduce sclp feature blocks, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 14/38] s390x/cpumodel: generate CPU feature lists for CPU models, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 04/38] s390/sclp: cache the sclp device,
Cornelia Huck <=
- [Qemu-devel] [PATCH for-2.8 05/38] s390x: wrap flic savevm calls into vmstate, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 07/38] s390x/css: handle cssid 255 correctly, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 16/38] s390x/cpumodel: introduce CPU feature group definitions, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 01/38] s390x: add compat machine for 2.8, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 26/38] s390x/sclp: propagate the mha via sclp, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 17/38] s390x/cpumodel: register defined CPU models as subclasses, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 25/38] s390x/sclp: propagate the ibc val (lowest and unblocked ibc), Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 21/38] s390x/cpumodel: check and apply the CPU model, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 06/38] s390x/ioinst: advertise fcs facility, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 38/38] s390x/cpumodel: implement QMP interface "query-cpu-model-baseline", Cornelia Huck, 2016/08/29