On 10/13/20 3:09 PM, Daniel Henrique Barboza wrote:
On 10/8/20 3:10 PM, Michal Privoznik wrote:
See 2/2 for detailed explanation.
Long story short - we can squeeze more bandwidth from TAP devices we
create for domains.
Michal Prívozník (2):
virnetdev: Introduce virNetDevSetRootQDisc()
qemu: Set noqueue qdisc for TAP devices
Reviewed-by: Daniel Henrique Barboza <danielhb413@xxxxxxxxx>
Thanks. Just before I merged these I realized that it will be a good
idea to mock virNetDevSetRootQDisc() so that we don't run tc from the
test suite. But the diff is really trivial:
diff --git i/src/util/virnetdev.h w/src/util/virnetdev.h
index 82943b8e08..dfef49938f 100644
--- i/src/util/virnetdev.h
+++ w/src/util/virnetdev.h
@@ -313,6 +313,7 @@ int virNetDevRunEthernetScript(const char *ifname,
const char *script)
G_GNUC_NO_INLINE;
int virNetDevSetRootQDisc(const char *ifname,
- const char *qdisc);
+ const char *qdisc)
+ G_GNUC_NO_INLINE;
G_DEFINE_AUTOPTR_CLEANUP_FUNC(virNetDevRxFilter, virNetDevRxFilterFree);
diff --git i/tests/qemuxml2argvmock.c w/tests/qemuxml2argvmock.c
index 9bf4357b66..b9322f4f2a 100644
--- i/tests/qemuxml2argvmock.c
+++ w/tests/qemuxml2argvmock.c
@@ -286,3 +286,11 @@ qemuBuildTPMOpenBackendFDs(const char *tpmdev
G_GNUC_UNUSED,
*cancelfd = 1731;
return 0;
}
+
+
+int
+virNetDevSetRootQDisc(const char *ifname G_GNUC_UNUSED,
+ const char *qdisc G_GNUC_UNUSED)
+{
+ return 0;
+}
Hopefully, you are okay if I squash this to 2/2.
Have you tried it out with older kernels? Reading the bug I understood
that 4.2 and older (2015 kernels) does not have qdisc support and that you
can, for example, test for NETIF_F_LLTX of the ETHTOOL_GFEATURES ioctl to
verify it.
I didn't, but I had this on mind when writing patches and I made the
whole thing best effort. Note that qemuDomainInterfaceSetDefaultQDisc()
retval is not checked for => if setting noqueue fails (for whatever
reason) then worst case scenario an error is printed into logs.
I consider this to be a 'nice to have' that can be added in a follow up
patch though, if applicable. By the way, do we have any documentation about
"the latest Libvirt release will not care about N+ years old kernel/QEMU"?
I'm not sure what you mean. This perhaps?
https://libvirt.org/platforms.html#linux-freebsd-and-macos
Michal
