Re: [Qemu-devel] [RFC] optimization for qcow2 cache get/put

2015-03-26 Thread Stefan Hajnoczi
On Mon, Jan 26, 2015 at 09:20:00PM +0800, Zhang Haoyu wrote: > Hi, all > > Regarding too large qcow2 image, e.g., 2TB, > so long disruption happened when performing snapshot, > which was caused by cache update and IO wait. I have CCed Kevin Wolf, the qcow2 maintainer. > perf top data shown as be

Re: [Qemu-devel] [RFC] optimization for qcow2 cache get/put

2015-01-26 Thread Zhang Haoyu
On 2015-01-27 09:24:13, Zhang Haoyu wrote: > > On 2015-01-26 22:11:59, Max Reitz wrote: > >On 2015-01-26 at 08:20, Zhang Haoyu wrote: >> > Hi, all > > > > > > Regarding too large qcow2 image, e.g., 2TB, > > > so long disruption happened when performing snapshot, > >> which was caused by cache upd

Re: [Qemu-devel] [RFC] optimization for qcow2 cache get/put

2015-01-26 Thread Zhang Haoyu
On 2015-01-26 22:11:59, Max Reitz wrote: >On 2015-01-26 at 08:20, Zhang Haoyu wrote: > > Hi, all > > > > Regarding too large qcow2 image, e.g., 2TB, > > so long disruption happened when performing snapshot, >> which was caused by cache update and IO wait. > > perf top data shown as below, > >

Re: [Qemu-devel] [RFC] optimization for qcow2 cache get/put

2015-01-26 Thread Max Reitz
On 2015-01-26 at 08:20, Zhang Haoyu wrote: Hi, all Regarding too large qcow2 image, e.g., 2TB, so long disruption happened when performing snapshot, which was caused by cache update and IO wait. perf top data shown as below, PerfTop:2554 irqs/sec kernel: 0.4% exact: 0.0% [4000Hz cycle

[Qemu-devel] [RFC] optimization for qcow2 cache get/put

2015-01-26 Thread Zhang Haoyu
Hi, all Regarding too large qcow2 image, e.g., 2TB, so long disruption happened when performing snapshot, which was caused by cache update and IO wait. perf top data shown as below, PerfTop:2554 irqs/sec kernel: 0.4% exact: 0.0% [4000Hz cycles], (target_pid: 34294)