Re: Performance Stats: Kernel patch

From: Maxim Uvarov
Date: Wed Apr 04 2007 - 09:15:38 EST

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Hello again,

Please see my answers bellow:

Valdis.Kletnieks@xxxxxx wrote:

On Tue, 03 Apr 2007 16:54:43 +0400, Maxim Uvarov said:

What do you think about it? Patch is bellow.

Was this patch actually compile and run tested?

Yes I have tested it on PPC, X86, X86_64, Mips targets.
It works.

Index: linux-2.6.18/fs/proc/array.c
===================================================================
--- linux-2.6.18.orig/fs/proc/array.c
+++ linux-2.6.18/fs/proc/array.c
@@ -295,6 +295,18 @@ static inline char *task_cap(struct task
cap_t(p->cap_effective));
}

+#ifdef THREAD_PERF_STAT

This needs to be CONFIG_THREAD_PERF_STAT everyplace except the Kconfig stuff.

Yes you are right. I have not check it after adding ifdef :(

+static inline char *task_perf(struct task_struct *p, char *buffer)
+{
+ return buffer + sprintf(buffer, "Nvcsw:\t%lu\n"
+ "Nivcsw:\t%lu\n"
+ "Syscalls:\t%d\n",
+ cap_t(p->nvcsw),
+ cap_t(p->nivcsw),
+ cap_t(p->sysc_cnt));
+}

You might want a #else that defines a null body for this inline, to
avoid a problem a bit later.

+#endif /* THREAD_PERF_STAT */
+
#define get_blocked_on(t) (-1)

static char *show_blocked_on(struct task_struct *task, char *buffer)
@@ -327,6 +339,7 @@ int proc_pid_status(struct task_struct *
buffer = task_show_regs(task, buffer);
#endif
buffer = show_blocked_on(task,buffer);
+ buffer = task_perf(task, buffer);

What will this call if you don't have THREAD_PERF_STAT defined?

Here's where you need the #else clause providing a null body for you....

I don't see how this could possibly have built cleanly, since the CONFIG_
issue above would have prevented you from defining a task_perf() function...

New version of this patch. Please flay it.

Signed-off-by: Max Uvarov <muvarov@xxxxxxxxxxxxx>
Description:
Patch adds Process Performance Statistics.

arch/i386/kernel/entry.S | 3 +++
arch/mips/kernel/entry.S | 3 +++
arch/powerpc/kernel/entry_32.S | 3 +++
arch/x86_64/kernel/entry.S | 3 +++
fs/proc/array.c | 17 +++++++++++++++++
include/linux/sched.h | 3 +++
kernel/fork.c | 3 +++
kernel/sys.c | 8 ++++++++
lib/Kconfig.debug | 17 +++++++++++++++++
9 files changed, 60 insertions(+)

Index: linux-2.6.18/fs/proc/array.c
===================================================================
--- linux-2.6.18.orig/fs/proc/array.c
+++ linux-2.6.18/fs/proc/array.c
@@ -295,6 +295,20 @@ static inline char *task_cap(struct task
cap_t(p->cap_effective));
}

+#ifdef CONFIG_THREAD_PERF_STAT
+static inline char *task_perf(struct task_struct *p, char *buffer)
+{
+#ifdef THREAD_PERF_STAT_SYSC
+ buffer += sprintf(buffer, "Syscalls:\t%d\n", cap_t(p->sysc_cnt));
+#endif /* THREAD_PERF_STAT_SYSC */
+
+ return buffer + sprintf(buffer, "Nvcsw:\t%lu\n"
+ "Nivcsw:\t%lu\n",
+ cap_t(p->nvcsw),
+ cap_t(p->nivcsw));
+}
+#endif /* CONFIG_THREAD_PERF_STAT */
+
#define get_blocked_on(t) (-1)

static char *show_blocked_on(struct task_struct *task, char *buffer)
@@ -327,6 +341,9 @@ int proc_pid_status(struct task_struct *
buffer = task_show_regs(task, buffer);
#endif
buffer = show_blocked_on(task,buffer);
+#ifdef CONFIG_THREAD_PERF_STAT
+ buffer = task_perf(task, buffer);
+#endif /* CONFIG_THREAD_PERF_STAT */
return buffer - orig;
}

Index: linux-2.6.18/include/linux/sched.h
===================================================================
--- linux-2.6.18.orig/include/linux/sched.h
+++ linux-2.6.18/include/linux/sched.h
@@ -1193,6 +1193,9 @@ struct task_struct {
ltt_facility_t ltt_facilities[LTT_FAC_PER_PROCESS];
#endif //CONFIG_LTT_USERSPACE_GENERIC

+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ int sysc_cnt; /* Syscall counter */
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
/*
* task-specic data
* XXX: for a future release, MontaVista-only
Index: linux-2.6.18/kernel/sys.c
===================================================================
--- linux-2.6.18.orig/kernel/sys.c
+++ linux-2.6.18/kernel/sys.c
@@ -2071,3 +2071,11 @@ asmlinkage long sys_prctl(int option, un
}
return error;
}
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+asmlinkage void inc_syscallcnt(void)
+{
+ current->sysc_cnt += 1;
+ return;
+}
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
+
Index: linux-2.6.18/kernel/fork.c
===================================================================
--- linux-2.6.18.orig/kernel/fork.c
+++ linux-2.6.18/kernel/fork.c
@@ -1079,6 +1079,9 @@ static struct task_struct *copy_process(
p->wchar = 0; /* I/O counter: bytes written */
p->syscr = 0; /* I/O counter: read syscalls */
p->syscw = 0; /* I/O counter: write syscalls */
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ p->sysc_cnt = 0; /* Syscall counter: total numbers of syscalls */
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
acct_clear_integrals(p);

p->it_virt_expires = cputime_zero;
Index: linux-2.6.18/arch/i386/kernel/entry.S
===================================================================
--- linux-2.6.18.orig/arch/i386/kernel/entry.S
+++ linux-2.6.18/arch/i386/kernel/entry.S
@@ -394,6 +394,9 @@ syscall_exit:
cli # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ call inc_syscallcnt # Increment syscalls counter current->sysc_cnt
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
testw $_TIF_ALLWORK_MASK, %cx # current->work
Index: linux-2.6.18/arch/x86_64/kernel/entry.S
===================================================================
--- linux-2.6.18.orig/arch/x86_64/kernel/entry.S
+++ linux-2.6.18/arch/x86_64/kernel/entry.S
@@ -388,6 +388,9 @@ ENTRY(int_ret_from_sys_call)
/* edi: mask to check */
int_with_check:
GET_THREAD_INFO(%rcx)
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ call inc_syscallcnt # Increment syscalls counter current->sysc_cnt
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
movl threadinfo_flags(%rcx),%edx
andl %edi,%edx
jnz int_careful
Index: linux-2.6.18/arch/powerpc/kernel/entry_32.S
===================================================================
--- linux-2.6.18.orig/arch/powerpc/kernel/entry_32.S
+++ linux-2.6.18/arch/powerpc/kernel/entry_32.S
@@ -236,6 +236,9 @@ ret_from_syscall:
#ifdef SHOW_SYSCALLS
bl do_show_syscall_exit
#endif
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ bl inc_syscallcnt /* Increment syscalls counter current->sysc_cnt */
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
#ifdef CONFIG_MICROSTATE
/* FIXME: this is too early since this might not return to
user space just yet because of syscall_exit_work */
Index: linux-2.6.18/arch/mips/kernel/entry.S
===================================================================
--- linux-2.6.18.orig/arch/mips/kernel/entry.S
+++ linux-2.6.18/arch/mips/kernel/entry.S
@@ -75,6 +75,9 @@ FEXPORT(syscall_exit)
raw_local_irq_disable # make sure need_resched and
# signals dont change between
# sampling and return
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ jal inc_syscallcnt # Increment syscalls counter current->sysc_cnt
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
LONG_L a2, TI_FLAGS($28) # current->work
li t0, _TIF_ALLWORK_MASK
and t0, a2, t0
Index: linux-2.6.18/lib/Kconfig.debug
===================================================================
--- linux-2.6.18.orig/lib/Kconfig.debug
+++ linux-2.6.18/lib/Kconfig.debug
@@ -539,4 +539,21 @@ config RCU_TORTURE_TEST
Say M if you want the RCU torture tests to build as a module.
Say N if you are unsure.

+config THREAD_PERF_STAT
+ bool "Per-process (thread) performance statistics"
+ depends on (X86 || PPC || MIPS)
+ help
+ Make available to the user the following new per-process (thread) performance statistics:
+ * Involuntary Context Switches
+ * Voluntary Context Switches
+ * Number of system calls (option)
+ This information is available via /proc/PID/status.
+
+config THREAD_PERF_STAT_SYSC
+ bool "enable syscall counter"
+ depends on THREAD_PERF_STAT
+ help
+ This option add syscalls counter to /proc/PID/status.
+
+
source "lib/Kconfig.kgdb"

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Next message: Christian Kujau: "Re: 2.6.20.4: NETDEV WATCHDOG and lockups"
Previous message: Arnd Bergmann: "Re: A set of "standard" virtual devices?"
In reply to: Valdis . Kletnieks: "Re: Performance Stats: Kernel patch"
Next in thread: Eric Dumazet: "Re: Performance Stats: Kernel patch"
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