From: William Lee Irwin III <wli@holomorphy.com>
To: Arjan van de Ven <arjanv@redhat.com>,
Andrew Morton <akpm@osdl.org>, Con Kolivas <kernel@kolivas.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Instrumenting high latency
Date: Mon, 12 Jul 2004 01:47:48 -0700 [thread overview]
Message-ID: <20040712084748.GY21066@holomorphy.com> (raw)
In-Reply-To: <20040712084231.GX21066@holomorphy.com>
On Mon, Jul 12, 2004 at 10:29:40AM +0200, Arjan van de Ven wrote:
>> ... or reset the time(r) in need_resched() under the assumption that all
>> need_resched() callers will yield when it returns true...
On Mon, Jul 12, 2004 at 01:42:31AM -0700, William Lee Irwin III wrote:
> Might be a good enough approximation. Two examples and a counterexample...
Index: timing-2.6.7/include/linux/sched.h
===================================================================
--- timing-2.6.7.orig/include/linux/sched.h 2004-06-15 22:18:57.000000000 -0700
+++ timing-2.6.7/include/linux/sched.h 2004-07-12 01:45:08.000000000 -0700
@@ -1000,7 +1000,8 @@
return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
}
-static inline int need_resched(void)
+#define need_resched() ({ touch_preempt_timing(); __need_resched(); })
+static inline int __need_resched(void)
{
return unlikely(test_thread_flag(TIF_NEED_RESCHED));
}
Index: timing-2.6.7/include/linux/preempt.h
===================================================================
--- timing-2.6.7.orig/include/linux/preempt.h 2004-07-11 04:33:55.000000000 -0700
+++ timing-2.6.7/include/linux/preempt.h 2004-07-12 01:18:17.000000000 -0700
@@ -12,7 +12,9 @@
#ifdef CONFIG_PREEMPT_TIMING
void __inc_preempt_count(void);
void __dec_preempt_count(void);
+void touch_preempt_timing(void);
#else
+#define touch_preempt_timing() do { } while (0)
#ifdef CONFIG_PREEMPT
#define __inc_preempt_count() do { preempt_count()++; } while (0)
#define __dec_preempt_count() do { preempt_count()--; } while (0)
Index: timing-2.6.7/arch/i386/kernel/traps.c
===================================================================
--- timing-2.6.7.orig/arch/i386/kernel/traps.c 2004-07-12 00:10:27.000000000 -0700
+++ timing-2.6.7/arch/i386/kernel/traps.c 2004-07-12 01:34:58.000000000 -0700
@@ -969,14 +969,24 @@
}
__setup("preempt_thresh=", setup_preempt_thresh);
+static void __touch_preempt_timing(void *addr)
+{
+ rdtscll(__get_cpu_var(preempt_timings));
+ __get_cpu_var(preempt_entry) = (unsigned long)addr;
+}
+
+void touch_preempt_timing(void)
+{
+ if (preempt_count() == 1 && system_state == SYSTEM_RUNNING)
+ __touch_preempt_timing(__builtin_return_address(0));
+}
+EXPORT_SYMBOL(touch_preempt_timing);
+
void __inc_preempt_count(void)
{
preempt_count()++;
- if (preempt_count() == 1 && system_state == SYSTEM_RUNNING) {
- rdtscll(__get_cpu_var(preempt_timings));
- __get_cpu_var(preempt_entry)
- = (unsigned long)__builtin_return_address(0);
- }
+ if (preempt_count() == 1 && system_state == SYSTEM_RUNNING)
+ __touch_preempt_timing(__builtin_return_address(0));
}
EXPORT_SYMBOL(__inc_preempt_count);
next prev parent reply other threads:[~2004-07-12 8:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-12 6:29 [PATCH] Instrumenting high latency Con Kolivas
2004-07-12 6:37 ` Andrew Morton
2004-07-12 6:43 ` Con Kolivas
2004-07-12 6:58 ` Andrew Morton
2004-07-12 7:00 ` [PATCH] " William Lee Irwin III
2004-07-12 7:34 ` Andrew Morton
2004-07-12 8:02 ` William Lee Irwin III
2004-07-12 8:38 ` William Lee Irwin III
2004-07-12 11:31 ` William Lee Irwin III
2004-07-12 14:32 ` William Lee Irwin III
2004-07-12 17:09 ` Martin Josefsson
2004-07-12 8:29 ` Arjan van de Ven
2004-07-12 8:42 ` William Lee Irwin III
2004-07-12 8:47 ` William Lee Irwin III [this message]
2004-07-12 10:41 ` Rajput
2004-07-12 10:44 ` William Lee Irwin III
2004-07-12 14:24 ` Martin J. Bligh
2004-07-12 14:27 ` Con Kolivas
2004-07-12 14:33 ` Martin J. Bligh
2004-07-12 14:42 ` Con Kolivas
2004-07-12 14:47 ` Martin J. Bligh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20040712084748.GY21066@holomorphy.com \
--to=wli@holomorphy.com \
--cc=akpm@osdl.org \
--cc=arjanv@redhat.com \
--cc=kernel@kolivas.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.