| Message ID | 20200131121111.130355-4-tz.stoyanov@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Timestamp synchronization of host - guest tracing session | expand |
On Fri, 31 Jan 2020 14:10:59 +0200 "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote: > From: Tzvetomir Stoyanov <tstoyanov@vmware.com> > > In order to match host and guest events, a mapping between guest VCPU > and the host task, running this VCPU is needed. Extended existing > struct guest to hold such mapping and added logic in read_qemu_guests() > function to initialize it. Implemented a new internal API, > get_guest_vcpu_pid(), to retrieve VCPU-task mapping for given VM. > > Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com> > --- > tracecmd/include/trace-local.h | 2 ++ > tracecmd/trace-record.c | 54 ++++++++++++++++++++++++++++++++++ > 2 files changed, 56 insertions(+) > > diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h > index 29f2779..a5cf064 100644 > --- a/tracecmd/include/trace-local.h > +++ b/tracecmd/include/trace-local.h > @@ -247,6 +247,8 @@ void update_first_instance(struct buffer_instance *instance, int topt); > > void show_instance_file(struct buffer_instance *instance, const char *name); > > +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu); > + > /* moved from trace-cmd.h */ > void tracecmd_create_top_instance(char *name); > void tracecmd_remove_instances(void); > diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c > index 28fe31b..b479e91 100644 > --- a/tracecmd/trace-record.c > +++ b/tracecmd/trace-record.c > @@ -3031,10 +3031,12 @@ static bool is_digits(const char *s) > return true; > } > > +#define VCPUS_MAX 256 > struct guest { > char *name; > int cid; > int pid; > + int cpu_pid[VCPUS_MAX]; Although this is probably fine for the near future, I don't like arbitrary limits that don't have to do with max sizes of the storage unit (like max int). Why is the cpu_pid a static array and not one that is allocated? We could use realloc, couldn't we, in the loading of it? -- Steve > }; > > static struct guest *guests; > @@ -3052,6 +3054,43 @@ static char *get_qemu_guest_name(char *arg) > return arg; > } > > +static void read_qemu_guests_pids(char *guest_task, struct guest *guest) > +{ > + struct dirent *entry; > + char path[PATH_MAX]; > + char *buf = NULL; > + size_t n = 0; > + int vcpu; > + DIR *dir; > + FILE *f; > + > + snprintf(path, sizeof(path), "/proc/%s/task", guest_task); > + dir = opendir(path); > + if (!dir) > + return; > + > + while ((entry = readdir(dir))) { > + if (!(entry->d_type == DT_DIR && is_digits(entry->d_name))) > + continue; > + > + snprintf(path, sizeof(path), "/proc/%s/task/%s/comm", > + guest_task, entry->d_name); > + f = fopen(path, "r"); > + if (!f) > + continue; > + > + if (getline(&buf, &n, f) >= 0 && > + strncmp(buf, "CPU ", 4) == 0) { > + vcpu = atoi(buf + 4); > + if (vcpu >= 0 && vcpu < VCPUS_MAX) > + guest->cpu_pid[vcpu] = atoi(entry->d_name); > + } > + > + fclose(f); > + } > + free(buf); > +} > + > static void read_qemu_guests(void) > { > static bool initialized; > @@ -3115,6 +3154,8 @@ static void read_qemu_guests(void) > if (!is_qemu) > goto next; > > + read_qemu_guests_pids(entry->d_name, &guest); > + > guests = realloc(guests, (guests_len + 1) * sizeof(*guests)); > if (!guests) > die("Can not allocate guest buffer"); > @@ -3160,6 +3201,19 @@ static char *parse_guest_name(char *guest, int *cid, int *port) > return guest; > } > > +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu) > +{ > + int i; > + > + if (!guests || guest_vcpu >= VCPUS_MAX) > + return -1; > + > + for (i = 0; i < guests_len; i++) > + if (guest_cid == guests[i].cid) > + return guests[i].cpu_pid[guest_vcpu]; > + return -1; > +} > + > static void set_prio(int prio) > { > struct sched_param sp;
On Thu, Feb 27, 2020 at 6:13 AM Steven Rostedt <rostedt@goodmis.org> wrote: > > On Fri, 31 Jan 2020 14:10:59 +0200 > "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote: > > > From: Tzvetomir Stoyanov <tstoyanov@vmware.com> > > > > In order to match host and guest events, a mapping between guest VCPU > > and the host task, running this VCPU is needed. Extended existing > > struct guest to hold such mapping and added logic in read_qemu_guests() > > function to initialize it. Implemented a new internal API, > > get_guest_vcpu_pid(), to retrieve VCPU-task mapping for given VM. > > > > Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com> > > --- > > tracecmd/include/trace-local.h | 2 ++ > > tracecmd/trace-record.c | 54 ++++++++++++++++++++++++++++++++++ > > 2 files changed, 56 insertions(+) > > > > diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h > > index 29f2779..a5cf064 100644 > > --- a/tracecmd/include/trace-local.h > > +++ b/tracecmd/include/trace-local.h > > @@ -247,6 +247,8 @@ void update_first_instance(struct buffer_instance *instance, int topt); > > > > void show_instance_file(struct buffer_instance *instance, const char *name); > > > > +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu); > > + > > /* moved from trace-cmd.h */ > > void tracecmd_create_top_instance(char *name); > > void tracecmd_remove_instances(void); > > diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c > > index 28fe31b..b479e91 100644 > > --- a/tracecmd/trace-record.c > > +++ b/tracecmd/trace-record.c > > @@ -3031,10 +3031,12 @@ static bool is_digits(const char *s) > > return true; > > } > > > > +#define VCPUS_MAX 256 > > struct guest { > > char *name; > > int cid; > > int pid; > > + int cpu_pid[VCPUS_MAX]; > > Although this is probably fine for the near future, I don't like > arbitrary limits that don't have to do with max sizes of the storage > unit (like max int). > > Why is the cpu_pid a static array and not one that is allocated? We > could use realloc, couldn't we, in the loading of it? > I did it to simplify the PoC implementation and never changed it to be a dynamic array, I'll reimplement it now. Thanks Steven! > -- Steve > > > }; > > > > static struct guest *guests; > > @@ -3052,6 +3054,43 @@ static char *get_qemu_guest_name(char *arg) > > return arg; > > } > > > > +static void read_qemu_guests_pids(char *guest_task, struct guest *guest) > > +{ > > + struct dirent *entry; > > + char path[PATH_MAX]; > > + char *buf = NULL; > > + size_t n = 0; > > + int vcpu; > > + DIR *dir; > > + FILE *f; > > + > > + snprintf(path, sizeof(path), "/proc/%s/task", guest_task); > > + dir = opendir(path); > > + if (!dir) > > + return; > > + > > + while ((entry = readdir(dir))) { > > + if (!(entry->d_type == DT_DIR && is_digits(entry->d_name))) > > + continue; > > + > > + snprintf(path, sizeof(path), "/proc/%s/task/%s/comm", > > + guest_task, entry->d_name); > > + f = fopen(path, "r"); > > + if (!f) > > + continue; > > + > > + if (getline(&buf, &n, f) >= 0 && > > + strncmp(buf, "CPU ", 4) == 0) { > > + vcpu = atoi(buf + 4); > > + if (vcpu >= 0 && vcpu < VCPUS_MAX) > > + guest->cpu_pid[vcpu] = atoi(entry->d_name); > > + } > > + > > + fclose(f); > > + } > > + free(buf); > > +} > > + > > static void read_qemu_guests(void) > > { > > static bool initialized; > > @@ -3115,6 +3154,8 @@ static void read_qemu_guests(void) > > if (!is_qemu) > > goto next; > > > > + read_qemu_guests_pids(entry->d_name, &guest); > > + > > guests = realloc(guests, (guests_len + 1) * sizeof(*guests)); > > if (!guests) > > die("Can not allocate guest buffer"); > > @@ -3160,6 +3201,19 @@ static char *parse_guest_name(char *guest, int *cid, int *port) > > return guest; > > } > > > > +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu) > > +{ > > + int i; > > + > > + if (!guests || guest_vcpu >= VCPUS_MAX) > > + return -1; > > + > > + for (i = 0; i < guests_len; i++) > > + if (guest_cid == guests[i].cid) > > + return guests[i].cpu_pid[guest_vcpu]; > > + return -1; > > +} > > + > > static void set_prio(int prio) > > { > > struct sched_param sp; >
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h index 29f2779..a5cf064 100644 --- a/tracecmd/include/trace-local.h +++ b/tracecmd/include/trace-local.h @@ -247,6 +247,8 @@ void update_first_instance(struct buffer_instance *instance, int topt); void show_instance_file(struct buffer_instance *instance, const char *name); +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu); + /* moved from trace-cmd.h */ void tracecmd_create_top_instance(char *name); void tracecmd_remove_instances(void); diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c index 28fe31b..b479e91 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -3031,10 +3031,12 @@ static bool is_digits(const char *s) return true; } +#define VCPUS_MAX 256 struct guest { char *name; int cid; int pid; + int cpu_pid[VCPUS_MAX]; }; static struct guest *guests; @@ -3052,6 +3054,43 @@ static char *get_qemu_guest_name(char *arg) return arg; } +static void read_qemu_guests_pids(char *guest_task, struct guest *guest) +{ + struct dirent *entry; + char path[PATH_MAX]; + char *buf = NULL; + size_t n = 0; + int vcpu; + DIR *dir; + FILE *f; + + snprintf(path, sizeof(path), "/proc/%s/task", guest_task); + dir = opendir(path); + if (!dir) + return; + + while ((entry = readdir(dir))) { + if (!(entry->d_type == DT_DIR && is_digits(entry->d_name))) + continue; + + snprintf(path, sizeof(path), "/proc/%s/task/%s/comm", + guest_task, entry->d_name); + f = fopen(path, "r"); + if (!f) + continue; + + if (getline(&buf, &n, f) >= 0 && + strncmp(buf, "CPU ", 4) == 0) { + vcpu = atoi(buf + 4); + if (vcpu >= 0 && vcpu < VCPUS_MAX) + guest->cpu_pid[vcpu] = atoi(entry->d_name); + } + + fclose(f); + } + free(buf); +} + static void read_qemu_guests(void) { static bool initialized; @@ -3115,6 +3154,8 @@ static void read_qemu_guests(void) if (!is_qemu) goto next; + read_qemu_guests_pids(entry->d_name, &guest); + guests = realloc(guests, (guests_len + 1) * sizeof(*guests)); if (!guests) die("Can not allocate guest buffer"); @@ -3160,6 +3201,19 @@ static char *parse_guest_name(char *guest, int *cid, int *port) return guest; } +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu) +{ + int i; + + if (!guests || guest_vcpu >= VCPUS_MAX) + return -1; + + for (i = 0; i < guests_len; i++) + if (guest_cid == guests[i].cid) + return guests[i].cpu_pid[guest_vcpu]; + return -1; +} + static void set_prio(int prio) { struct sched_param sp;