| Message ID | 20230509111202.333714-4-nrb@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: s390: add counters for vsie performance | expand |
On Tue, 9 May 2023 13:12:02 +0200 Nico Boehr <nrb@linux.ibm.com> wrote: > The gmap notifier is called whenever something in the gmap structures this is a little bit too oversimplified; the gmap notifier is only called for ptes (or pmds for hugetlbfs) that have the notifier bit set (used for prefix or vsie) > changes. To diagnose performance issues, it can be useful to see what > causes certain changes in the gmap. > > Hence, add a tracepoint in the gmap notifier. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> apart for the above nit, looks quite straightforward > --- > arch/s390/kvm/kvm-s390.c | 2 ++ > arch/s390/kvm/trace-s390.h | 23 +++++++++++++++++++++++ > 2 files changed, 25 insertions(+) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index b012645a5a7c..f66953bdabe4 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -3981,6 +3981,8 @@ static void kvm_gmap_notifier(struct gmap *gmap, unsigned long start, > unsigned long prefix; > unsigned long i; > > + trace_kvm_s390_gmap_notifier(start, end, gmap_is_shadow(gmap)); > + > if (gmap_is_shadow(gmap)) > return; > if (start >= 1UL << 31) > diff --git a/arch/s390/kvm/trace-s390.h b/arch/s390/kvm/trace-s390.h > index 6f0209d45164..5dabd0b64d6e 100644 > --- a/arch/s390/kvm/trace-s390.h > +++ b/arch/s390/kvm/trace-s390.h > @@ -333,6 +333,29 @@ TRACE_EVENT(kvm_s390_airq_suppressed, > __entry->id, __entry->isc) > ); > > +/* > + * Trace point for gmap notifier calls. > + */ > +TRACE_EVENT(kvm_s390_gmap_notifier, > + TP_PROTO(unsigned long start, unsigned long end, unsigned int shadow), > + TP_ARGS(start, end, shadow), > + > + TP_STRUCT__entry( > + __field(unsigned long, start) > + __field(unsigned long, end) > + __field(unsigned int, shadow) > + ), > + > + TP_fast_assign( > + __entry->start = start; > + __entry->end = end; > + __entry->shadow = shadow; > + ), > + > + TP_printk("gmap notified (start:0x%lx end:0x%lx shadow:%d)", > + __entry->start, __entry->end, __entry->shadow) > + ); > + > > #endif /* _TRACE_KVMS390_H */ >
Quoting Claudio Imbrenda (2023-05-09 13:48:39) > On Tue, 9 May 2023 13:12:02 +0200 > Nico Boehr <nrb@linux.ibm.com> wrote: > > > The gmap notifier is called whenever something in the gmap structures > > this is a little bit too oversimplified; the gmap notifier is only > called for ptes (or pmds for hugetlbfs) that have the notifier bit set > (used for prefix or vsie) Yep true, I will adjust, thanks.
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index b012645a5a7c..f66953bdabe4 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3981,6 +3981,8 @@ static void kvm_gmap_notifier(struct gmap *gmap, unsigned long start, unsigned long prefix; unsigned long i; + trace_kvm_s390_gmap_notifier(start, end, gmap_is_shadow(gmap)); + if (gmap_is_shadow(gmap)) return; if (start >= 1UL << 31) diff --git a/arch/s390/kvm/trace-s390.h b/arch/s390/kvm/trace-s390.h index 6f0209d45164..5dabd0b64d6e 100644 --- a/arch/s390/kvm/trace-s390.h +++ b/arch/s390/kvm/trace-s390.h @@ -333,6 +333,29 @@ TRACE_EVENT(kvm_s390_airq_suppressed, __entry->id, __entry->isc) ); +/* + * Trace point for gmap notifier calls. + */ +TRACE_EVENT(kvm_s390_gmap_notifier, + TP_PROTO(unsigned long start, unsigned long end, unsigned int shadow), + TP_ARGS(start, end, shadow), + + TP_STRUCT__entry( + __field(unsigned long, start) + __field(unsigned long, end) + __field(unsigned int, shadow) + ), + + TP_fast_assign( + __entry->start = start; + __entry->end = end; + __entry->shadow = shadow; + ), + + TP_printk("gmap notified (start:0x%lx end:0x%lx shadow:%d)", + __entry->start, __entry->end, __entry->shadow) + ); + #endif /* _TRACE_KVMS390_H */
The gmap notifier is called whenever something in the gmap structures changes. To diagnose performance issues, it can be useful to see what causes certain changes in the gmap. Hence, add a tracepoint in the gmap notifier. Signed-off-by: Nico Boehr <nrb@linux.ibm.com> --- arch/s390/kvm/kvm-s390.c | 2 ++ arch/s390/kvm/trace-s390.h | 23 +++++++++++++++++++++++ 2 files changed, 25 insertions(+)