diff --git a/arch/x86/kernel/include/syscall_list.h b/arch/x86/kernel/include/syscall_list.h
index af7fb177..b0775db2 100644
--- a/arch/x86/kernel/include/syscall_list.h
+++ b/arch/x86/kernel/include/syscall_list.h
@@ -61,6 +61,7 @@ SYSCALL_DELEGATED(102, getuid)
 SYSCALL_DELEGATED(104, getgid)
 SYSCALL_DELEGATED(107, geteuid)
 SYSCALL_DELEGATED(108, getegid)
+SYSCALL_HANDLED(109, setpgid)
 SYSCALL_DELEGATED(110, getppid)
 SYSCALL_DELEGATED(111, getpgrp)
 SYSCALL_HANDLED(127, rt_sigpending)
diff --git a/arch/x86/kernel/syscall.c b/arch/x86/kernel/syscall.c
index d9fc3d86..34f9e582 100644
--- a/arch/x86/kernel/syscall.c
+++ b/arch/x86/kernel/syscall.c
@@ -159,6 +159,34 @@ extern unsigned long do_kill(int pid, int tid, int sig);
 extern void interrupt_syscall(int all, int pid);
 extern int num_processors;
 
+void
+do_setpgid(int pid, int pgid)
+{
+	struct cpu_local_var *v;
+	struct process *p;
+	struct process *proc = cpu_local_var(current);
+	int i;
+	unsigned long irqstate;
+
+	if(pid == 0)
+		pid = proc->pid;
+	if(pgid == 0)
+		pgid = pid;
+
+	for(i = 0; i < num_processors; i++){
+		v = get_cpu_local_var(i);
+		irqstate = ihk_mc_spinlock_lock(&(v->runq_lock));
+		list_for_each_entry(p, &(v->runq), sched_list){
+			if(p->pid <= 0)
+				continue;
+			if(p->pid == pid){
+				p->pgid = pgid;
+			}
+		}
+		ihk_mc_spinlock_unlock(&(v->runq_lock), irqstate);
+	}
+}
+
 void
 do_signal(unsigned long rc, void *regs0, struct process *proc, struct sig_pending *pending)
 {
@@ -319,6 +347,52 @@ do_kill(int pid, int tid, int sig)
 	if(sig > 64 || sig < 0)
 		return -EINVAL;
 
+	if(tid == -1 && pid <= 0){
+		int	pgid = -pid;
+		int	rc = -ESRCH;
+		int	*pids;
+		int	i;
+		int	n = 0;
+		int	sendme = 0;
+
+		pids = kmalloc(sizeof(int) * num_processors, IHK_MC_AP_NOWAIT);
+		if(!pids)
+			return -ENOMEM;
+		if(pid == 0)
+			pgid = proc->pgid;
+		for(i = 0; i < num_processors; i++){
+			v = get_cpu_local_var(i);
+			irqstate = ihk_mc_spinlock_lock(&(v->runq_lock));
+			list_for_each_entry(p, &(v->runq), sched_list){
+				if(p->pid <= 0)
+					continue;
+				if(p->pid == proc->pid){
+					sendme = 1;
+					continue;
+				}
+				if(pgid == 1 || p->pgid == pgid){
+					int	j;
+
+					for(j = 0; j < n; j++)
+						if(pids[j] == p->pid)
+							break;
+					if(j == n){
+						pids[n] = p->pid;
+						n++;
+					}
+				}
+			}
+			ihk_mc_spinlock_unlock(&(v->runq_lock), irqstate);
+		}
+		for(i = 0; i < n; i++)
+			rc = do_kill(pids[i], -1, sig);
+		if(sendme)
+			rc = do_kill(proc->pid, -1, sig);
+
+		kfree(pids);
+		return rc;
+	}
+
 	mask = __sigmask(sig);
 	if(tid == -1){
 		struct process *tproc0 = NULL;
@@ -381,7 +455,6 @@ do_kill(int pid, int tid, int sig)
 	if(sig == 0)
 		return 0;
 
-
 	doint = 0;
 	if(tid == -1){
 		irqstate = ihk_mc_spinlock_lock(&tproc->sigshared->lock);
diff --git a/executer/include/uprotocol.h b/executer/include/uprotocol.h
index 87b53892..cb2e95c7 100644
--- a/executer/include/uprotocol.h
+++ b/executer/include/uprotocol.h
@@ -70,6 +70,7 @@ struct program_load_desc {
 	int pid;
 	int err;
 	int stack_prot;
+	int pgid;
 	unsigned long entry;
 	unsigned long user_start;
 	unsigned long user_end;
diff --git a/executer/user/mcexec.c b/executer/user/mcexec.c
index 647b665d..90f1c51d 100644
--- a/executer/user/mcexec.c
+++ b/executer/user/mcexec.c
@@ -215,6 +215,7 @@ struct program_load_desc *load_elf(FILE *fp, char **interp_pathp)
 		}
 	}
 	desc->pid = getpid();
+	desc->pgid = getpgid(0);
 	desc->entry = hdr.e_entry;
 
 	desc->at_phdr = load_addr + hdr.e_phoff;
diff --git a/kernel/host.c b/kernel/host.c
index 7f469fa1..2330972c 100644
--- a/kernel/host.c
+++ b/kernel/host.c
@@ -391,6 +391,7 @@ static int process_msg_prepare_process(unsigned long rphys)
 	}
 	proc->pid = pn->pid;
 	proc->tid = pn->pid;
+	proc->pgid = pn->pgid;
 	proc->ftn->pid = pn->pid;
 	proc->vm->region.user_start = pn->user_start;
 	proc->vm->region.user_end = pn->user_end;
diff --git a/kernel/include/process.h b/kernel/include/process.h
index 09ea47e0..f3a9e4eb 100644
--- a/kernel/include/process.h
+++ b/kernel/include/process.h
@@ -194,6 +194,7 @@ struct process {
 
 	cpu_set_t cpu_set;
 	unsigned long saved_auxv[AUXV_LEN];
+	int pgid;	/* process group id */
 };
 
 struct process_vm {
diff --git a/kernel/include/syscall.h b/kernel/include/syscall.h
index fcb718fe..d04d9a90 100644
--- a/kernel/include/syscall.h
+++ b/kernel/include/syscall.h
@@ -110,6 +110,7 @@ struct program_load_desc {
 	int pid;
 	int err;
 	int stack_prot;
+	int pgid;
 	unsigned long entry;
 	unsigned long user_start;
 	unsigned long user_end;
diff --git a/kernel/syscall.c b/kernel/syscall.c
index 7b1593e2..1b64b233 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -98,6 +98,7 @@ void do_signal(long rc, void *regs, struct process *proc, struct sig_pending *pe
 extern unsigned long do_kill(int pid, int tid, int sig);
 int copy_from_user(struct process *, void *, const void *, size_t);
 int copy_to_user(struct process *, void *, const void *, size_t);
+void do_setpgid(int, int);
 
 int prepare_process_ranges_args_envs(struct process *proc, 
 		struct program_load_desc *pn,
@@ -1318,6 +1319,8 @@ SYSCALL_DECLARE(clone)
 		return -ENOMEM;
 	}
 
+	new->pgid = cpu_local_var(current)->pgid;
+
 	cpu_set(cpuid, &new->vm->cpu_set, &new->vm->cpu_set_lock);
 
 	if (clone_flags & CLONE_VM) {
@@ -1430,10 +1433,28 @@ SYSCALL_DECLARE(kill)
 SYSCALL_DECLARE(tgkill)
 {
 	int tgid = ihk_mc_syscall_arg0(ctx);
-	int pid = ihk_mc_syscall_arg1(ctx);
+	int tid = ihk_mc_syscall_arg1(ctx);
 	int sig = ihk_mc_syscall_arg2(ctx);
 
-	return do_kill(tgid, pid, sig);
+	if(tid <= 0)
+		return -EINVAL;
+	if(tgid <= 0 && tgid != -1)
+		return -EINVAL;
+
+	return do_kill(tgid, tid, sig);
+}
+
+SYSCALL_DECLARE(setpgid)
+{
+	int pid = ihk_mc_syscall_arg0(ctx);
+	int pgid = ihk_mc_syscall_arg1(ctx);
+	long rc;
+
+	rc = syscall_generic_forwarding(__NR_setpgid, ctx);
+	if(rc == 0){
+		do_setpgid(pid, pgid);
+	}
+	return rc;
 }
 
 SYSCALL_DECLARE(set_robust_list)