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27af7d6ea5
Avoid hot pages being replaced by others to remarkably decrease cache
misses
Sample results with the test program which quote from xbzrle.txt ran in
vm:(migrate bandwidth:1GE and xbzrle cache size 8MB)
the test program:
include <stdlib.h>
include <stdio.h>
int main()
{
char *buf = (char *) calloc(4096, 4096);
while (1) {
int i;
for (i = 0; i < 4096 * 4; i++) {
buf[i * 4096 / 4]++;
}
printf(".");
}
}
before this patch:
virsh qemu-monitor-command test_vm '{"execute": "query-migrate"}'
{"return":{"expected-downtime":1020,"xbzrle-cache":{"bytes":1108284,
"cache-size":8388608,"cache-miss-rate":0.987013,"pages":18297,"overflow":8,
"cache-miss":1228737},"status":"active","setup-time":10,"total-time":52398,
"ram":{"total":12466991104,"remaining":1695744,"mbps":935.559472,
"transferred":5780760580,"dirty-sync-counter":271,"duplicate":2878530,
"dirty-pages-rate":29130,"skipped":0,"normal-bytes":5748592640,
"normal":1403465}},"id":"libvirt-706"}
18k pages sent compressed in 52 seconds.
cache-miss-rate is 98.7%, totally miss.
after optimizing:
virsh qemu-monitor-command test_vm '{"execute": "query-migrate"}'
{"return":{"expected-downtime":2054,"xbzrle-cache":{"bytes":5066763,
"cache-size":8388608,"cache-miss-rate":0.485924,"pages":194823,"overflow":0,
"cache-miss":210653},"status":"active","setup-time":11,"total-time":18729,
"ram":{"total":12466991104,"remaining":3895296,"mbps":937.663549,
"transferred":1615042219,"dirty-sync-counter":98,"duplicate":2869840,
"dirty-pages-rate":58781,"skipped":0,"normal-bytes":1588404224,
"normal":387794}},"id":"libvirt-266"}
194k pages sent compressed in 18 seconds.
The value of cache-miss-rate decrease to 48.59%.
Signed-off-by: ChenLiang <chenliang88@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
|
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|---|---|---|
| .. | ||
| qmp | ||
| specs | ||
| aio_notify.promela | ||
| atomics.txt | ||
| blkdebug.txt | ||
| blkverify.txt | ||
| bootindex.txt | ||
| ccid.txt | ||
| ich9-ehci-uhci.cfg | ||
| image-fuzzer.txt | ||
| libcacard.txt | ||
| live-block-ops.txt | ||
| memory.txt | ||
| migration.txt | ||
| multiple-iothreads.txt | ||
| multiseat.txt | ||
| q35-chipset.cfg | ||
| qapi-code-gen.txt | ||
| qdev-device-use.txt | ||
| qemupciserial.inf | ||
| rdma.txt | ||
| spice-port-fqdn.txt | ||
| tracing.txt | ||
| usb2.txt | ||
| usb-storage.txt | ||
| virtio-balloon-stats.txt | ||
| vnc-ledstate-Pseudo-encoding.txt | ||
| writing-qmp-commands.txt | ||
| xbzrle.txt | ||
| xen-save-devices-state.txt | ||