[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] RE: Reducing I/O introduced domain scheduling
Just wondering... does Xen/can Xen take VM exits on fences? If not then I don't see you could safely buffer MMIO writes. Paul > -----Original Message----- > From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel- > bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Dong, Eddie > Sent: 12 October 2010 02:12 > To: Keir Fraser > Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; Dong, Eddie; Zhang, Xiantao > Subject: [Xen-devel] Reducing I/O introduced domain scheduling > > Keir: > When running vConsolidation on top of Xen in a 4-core > platform, we noticed the I/O introduced scheduling per CPU is ~3K > Hz, which seems to be too frequent and cause frequent involve of > domain 0 / Qemu, which may polute cache of the guest and thus > increase CPI (cycle per instruction). > > We are thinking if we can reduce the domin switch here, and > think the output of I/O can be buffered and return immediately. The > buffered I/O can be flushed out at next IN emulation (or any > Hypervisor emulated I/O) or timeout such as 10 or 100 us to > guarantee minimal response. > > Ideally it can cover both PIO & MMIO, but we can start from > PIO. > > How do you think of that? > > Thx, Eddie > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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