| Message ID | Zd81gp2utD9+ripX@tpad (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [-v2,net-next] net/core/dev.c: enable timestamp static key if CPU isolation is configured | expand |
Marcelo Tosatti wrote: > > For systems that use CPU isolation (via nohz_full), creating or destroying > a socket with timestamping (SOCK_TIMESTAMPING_RX_SOFTWARE and > SOF_TIMESTAMPING_OPT_TX_SWHW) might cause a Again, SOF_TIMESTAMPING_OPT_TX_SWHW is irrelevant here. See Documentation/networking/timestamping.rst for a definition of the various flags. > static key to be enabled/disabled. This in turn causes undesired > IPIs to isolated CPUs. > > So enable the static key unconditionally, if CPU isolation is enabled, > thus avoiding the IPIs. > > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> > > --- > v2: mention SOF_TIMESTAMPING_OPT_TX_SWHW in the commit log (Willem de Bruijn / Paolo Abeni) I did not suggest that The subject line is slightly corrupted: net-next -v2 > > diff --git a/net/core/dev.c b/net/core/dev.c > index c588808be77f..15a32f5900e6 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -155,6 +155,7 @@ > #include <net/netdev_rx_queue.h> > #include <net/page_pool/types.h> > #include <net/page_pool/helpers.h> > +#include <linux/sched/isolation.h> > > #include "dev.h" > #include "net-sysfs.h" > @@ -11851,3 +11852,14 @@ static int __init net_dev_init(void) > } > > subsys_initcall(net_dev_init); > + > +static int __init net_dev_late_init(void) > +{ > + /* avoid static key IPIs to isolated CPUs */ > + if (housekeeping_enabled(HK_TYPE_MISC)) > + net_enable_timestamp(); > + > + return 0; > +} > + > +late_initcall(net_dev_late_init); >
diff --git a/net/core/dev.c b/net/core/dev.c index c588808be77f..15a32f5900e6 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -155,6 +155,7 @@ #include <net/netdev_rx_queue.h> #include <net/page_pool/types.h> #include <net/page_pool/helpers.h> +#include <linux/sched/isolation.h> #include "dev.h" #include "net-sysfs.h" @@ -11851,3 +11852,14 @@ static int __init net_dev_init(void) } subsys_initcall(net_dev_init); + +static int __init net_dev_late_init(void) +{ + /* avoid static key IPIs to isolated CPUs */ + if (housekeeping_enabled(HK_TYPE_MISC)) + net_enable_timestamp(); + + return 0; +} + +late_initcall(net_dev_late_init);
For systems that use CPU isolation (via nohz_full), creating or destroying a socket with timestamping (SOCK_TIMESTAMPING_RX_SOFTWARE and SOF_TIMESTAMPING_OPT_TX_SWHW) might cause a static key to be enabled/disabled. This in turn causes undesired IPIs to isolated CPUs. So enable the static key unconditionally, if CPU isolation is enabled, thus avoiding the IPIs. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> --- v2: mention SOF_TIMESTAMPING_OPT_TX_SWHW in the commit log (Willem de Bruijn / Paolo Abeni)