From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
To: rostedt@goodmis.org
Cc: linux-trace-devel@vger.kernel.org
Subject: [PATCH v16 07/18] trace-cmd: Find and store pids of tasks, which run virtual CPUs of given VM
Date: Fri, 29 Nov 2019 12:17:22 +0200 [thread overview]
Message-ID: <20191129101733.375808-8-tz.stoyanov@gmail.com> (raw)
In-Reply-To: <20191129101733.375808-1-tz.stoyanov@gmail.com>
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 | 57 ++++++++++++++++++++++++++++++++++
2 files changed, 59 insertions(+)
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index a51f0d0..51abef1 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -243,6 +243,8 @@ 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 4459c90..fd7ca82 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -2873,10 +2873,12 @@ 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;
@@ -2894,6 +2896,46 @@ 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)
+ goto next;
+ if (strncmp(buf, "CPU ", 4) != 0)
+ goto next;
+
+ vcpu = atoi(buf+4);
+ if (!(vcpu >= 0 && vcpu < VCPUS_MAX))
+ goto next;
+ guest->cpu_pid[vcpu] = atoi(entry->d_name);
+
+next:
+ fclose(f);
+ }
+ free(buf);
+}
+
static void read_qemu_guests(void)
{
static bool initialized;
@@ -2957,6 +2999,8 @@ 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");
@@ -3002,6 +3046,19 @@ 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;
--
2.23.0
next prev parent reply other threads:[~2019-11-29 10:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-29 10:17 [PATCH v16 00/18]Timestamp synchronization of host - guest tracing session Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 01/18] trace-cmd: Implement new lib API: tracecmd_local_events_system() Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 02/18] trace-cmd: Add support for negative time offsets in trace.dat file Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 03/18] trace-cmd: Add implementations of htonll() and ntohll() Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 04/18] trace-cmd: Add new library APIs for ftrace instances Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 05/18] trace-cmd: Add new library API for local CPU count Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 06/18] trace-cmd: Add new library API for reading ftrace buffers Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` Tzvetomir Stoyanov (VMware) [this message]
2019-11-29 10:17 ` [PATCH v16 08/18] trace-cmd: Implement new API tracecmd_add_option_v() Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 09/18] trace-cmd: Add new API to generate a unique ID of the tracing session Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 10/18] trace-cmd: Store the session tracing ID in the trace.dat file Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 11/18] trace-cmd: Exchange tracing IDs between host and guest Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 12/18] trace-cmd: Implement new option in trace.dat file: TRACECMD_OPTION_TIME_SHIFT Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 13/18] trace-cmd: Add guest information in host's trace.dat file Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 14/18] trace-cmd: Add host trace clock as guest trace argument Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 15/18] trace-cmd: Refactor few trace-cmd internal functions Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 16/18] trace-cmd: Basic infrastructure for host - guest timestamp synchronization Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 17/18] trace-cmd: [POC] PTP-like algorithm " Tzvetomir Stoyanov (VMware)
2019-11-29 10:17 ` [PATCH v16 18/18] trace-cmd: Debug scripts for " Tzvetomir Stoyanov (VMware)
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