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Date: Wed, 04 Apr 2007 20:52:34 +0400
From: Maxim Uvarov <muvarov@...mvista.com>
To: Eric Dumazet <dada1@...mosbay.com>
Cc: Valdis.Kletnieks@...edu, linux-kernel@...r.kernel.org
Subject: Re: Performance Stats: Kernel patch
Hello Eric,
I changed patch according to your comments.
Could you please take a look at it?
Eric Dumazet wrote:
>On Wed, 04 Apr 2007 17:15:43 +0400
>Maxim Uvarov <muvarov@...mvista.com> wrote:
>
>
>
>>--- 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 */
>>
>>
>
>Please dont call a function to do one increment !
>
>
Yes, you are right. I have changed it.
>You are touching one of the most critical part of the kernel...
>
>Also, dont do this while interrupts are masked, this is not necessary.
>
>Maybe better to place sysc_cnt in 'struct thread_info' because %ebp point to it.
>
>
>Also you missed the fact that syscalls on i386 can use sysenter (around line 343)
>
>
>
>> TRACE_IRQS_OFF
>> movl TI_flags(%ebp), %ecx
>> testw $_TIF_ALLWORK_MASK, %cx # current->work
>>
>>
>>
I rewrote this patch for x86. And I have question. Should /proc/PID/status
be used for these counters and this option be selectable or it will
better to
create another file in /proc/PID/ directory?
I will include syscall counters for other arches later.
P.S.
Jesper Juhl, thank you.
Best regards,
Maxim.
Signed-off-by: Max Uvarov <muvarov@...mvista.com>
Description:
Patch adds Process Performance Statistics.
arch/i386/kernel/asm-offsets.c | 3 +++
arch/i386/kernel/entry.S | 6 ++++++
fs/proc/array.c | 14 ++++++++++++++
include/asm/thread_info.h | 3 +++
kernel/fork.c | 3 +++
lib/Kconfig.debug | 16 ++++++++++++++++
6 files changed, 45 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 CONFIG_THREAD_PERF_STAT_SYSC
+ buffer += sprintf(buffer, "Syscalls:\t%lu\n",
cap_t(p->thread_info->sysc_cnt));
+#endif /* CONFIG_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)
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
@@ -334,6 +334,9 @@ sysenter_past_esp:
jae syscall_badsys
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp)
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ incl TI_sysc_cnt(%ebp) # Increment syscalls counter
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
#ifdef CONFIG_MICROSTATE
call msa_end_syscall
#endif
@@ -388,6 +391,9 @@ syscall_call:
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp) # store the return value
syscall_exit:
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ incl TI_sysc_cnt(%ebp) # Increment syscalls counter
current->sysc_cnt
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
#ifdef CONFIG_MICROSTATE
call msa_end_syscall
#endif
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 +539,20 @@ 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
+ help
+ Make available to the user the following per-process (thread)
performance statistics:
+ * Number of involuntary context switches
+ * Number of voluntary context switches
+ * Number of system calls (optional)
+ 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 adds a syscall counter to /proc/PID/status.
+
source "lib/Kconfig.kgdb"
Index: linux-2.6.18/include/asm/thread_info.h
===================================================================
--- linux-2.6.18.orig/include/asm/thread_info.h
+++ linux-2.6.18/include/asm/thread_info.h
@@ -44,6 +44,9 @@ struct thread_info {
of nested (IRQ) stacks
*/
__u8 supervisor_stack[0];
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ unsigned long sysc_cnt; /* Syscall counter */
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
};
#else /* !__ASSEMBLY__ */
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->thread_info->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/asm-offsets.c
===================================================================
--- linux-2.6.18.orig/arch/i386/kernel/asm-offsets.c
+++ linux-2.6.18/arch/i386/kernel/asm-offsets.c
@@ -56,6 +56,9 @@ void foo(void)
OFFSET(TI_addr_limit, thread_info, addr_limit);
OFFSET(TI_restart_block, thread_info, restart_block);
OFFSET(TI_sysenter_return, thread_info, sysenter_return);
+#ifdef CONFIG_THREAD_PERF_STAT_SYSC
+ OFFSET(TI_sysc_cnt, thread_info, sysc_cnt);
+#endif /* CONFIG_THREAD_PERF_STAT_SYSC */
BLANK();
-
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