From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
To: rostedt@goodmis.org
Cc: linux-trace-devel@vger.kernel.org
Subject: [PATCH v19 03/15] trace-cmd: Find and store pids of tasks, which run virtual CPUs of given VM
Date: Fri, 31 Jan 2020 14:10:59 +0200 [thread overview]
Message-ID: <20200131121111.130355-4-tz.stoyanov@gmail.com> (raw)
In-Reply-To: <20200131121111.130355-1-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 | 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];
};
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;
--
2.24.1
next prev parent reply other threads:[~2020-01-31 12:11 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 12:10 [PATCH v19 00/15]Timestamp synchronization of host - guest tracing session Tzvetomir Stoyanov (VMware)
2020-01-31 12:10 ` [PATCH v19 01/15] trace-cmd: Add support for negative time offsets in trace.dat file Tzvetomir Stoyanov (VMware)
2020-01-31 12:10 ` [PATCH v19 02/15] trace-cmd: Add new library API for local CPU count Tzvetomir Stoyanov (VMware)
2020-01-31 12:10 ` Tzvetomir Stoyanov (VMware) [this message]
2020-02-27 4:13 ` [PATCH v19 03/15] trace-cmd: Find and store pids of tasks, which run virtual CPUs of given VM Steven Rostedt
2020-02-27 8:30 ` Tzvetomir Stoyanov
2020-01-31 12:11 ` [PATCH v19 04/15] trace-cmd: Implement new API tracecmd_add_option_v() Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 05/15] trace-cmd: Add new API to generate a unique ID of the tracing session Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 06/15] trace-cmd: Store the session tracing ID in the trace.dat file Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 07/15] trace-cmd: Add definitions of htonll() and ntohll() Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 08/15] trace-cmd: Exchange tracing IDs between host and guest Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 09/15] trace-cmd: Implement new option in trace.dat file: TRACECMD_OPTION_TIME_SHIFT Tzvetomir Stoyanov (VMware)
2020-02-27 3:49 ` Steven Rostedt
2020-01-31 12:11 ` [PATCH v19 10/15] trace-cmd: Add guest information in host's trace.dat file Tzvetomir Stoyanov (VMware)
2020-02-27 3:53 ` Steven Rostedt
2020-02-27 3:56 ` Steven Rostedt
2020-02-27 9:39 ` Tzvetomir Stoyanov
2020-01-31 12:11 ` [PATCH v19 11/15] trace-cmd: Add host trace clock as guest trace argument Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 12/15] trace-cmd: Refactor few trace-cmd internal functions Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 13/15] trace-cmd: Basic infrastructure for host - guest timestamp synchronization Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 14/15] trace-cmd: [POC] PTP-like algorithm " Tzvetomir Stoyanov (VMware)
2020-01-31 12:11 ` [PATCH v19 15/15] trace-cmd: Debug scripts for " Tzvetomir Stoyanov (VMware)
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