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@gmail.com>
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