Re: [PATCH 5/5] KVM: paravirt time source

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Jeremy Fitzhardinge wrote:
Anthony Liguori wrote:
+static cycle_t read_hyper(void)
+{
+	struct timespec now;
+	int ret;
+
+	ret = kvm_hypercall(KVM_HYPERCALL_GET_KTIME, (u32)&now, 0, 0, 0);
+	WARN_ON(ret);
+
+	return now.tv_nsec + now.tv_sec * (cycles_t)1e9;

Hm, use of FP looks pretty odd.  I guess its OK to assume the compiler
will completely remove all the FP stuff at compile time.  Or you could
use NSEC_PER_SEC.

Agreed.

+}
+
+static struct clocksource clocksource_hyper = {
+	.name			= "hyper",
+	.rating			= 200,

We should probably standardize on this.  I guess that if you're in a
paravirt environment, and there's a paravirt clocksource, that would
always be the best clocksource to use.

+	.read			= read_hyper,
+	.mask			= CLOCKSOURCE_MASK(64),
+	.mult			= 1,
+	.shift			= 0,

It would be better to use a scale and shift here, so that adjtime has
something to work with when warping time.

Okay. I may remove this patch from the patch series and attempt to sit down next week and work out something more complete that also implements stolen time accounting.

Regards,

Anthony Liguori

    J


_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/virtualization

[Index of Archives]     [KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux