From: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@elte.hu, linux-kernel@vger.kernel.org,
Paul Mackerras <paulus@samba.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Greg Kroah-Hartman <gregkh@suse.de>
Subject: Re: [PATCH 0/5] lockdep: Add information of file and line to lockdep_map
Date: Sat, 16 Jan 2010 22:01:24 +0900 [thread overview]
Message-ID: <4B51B8A4.7010503@dcl.info.waseda.ac.jp> (raw)
In-Reply-To: <1263376323.4244.204.camel@laptop>
On 2010年01月13日 18:52, Peter Zijlstra wrote:
> On Thu, 2010-01-07 at 19:39 +0900, Hitoshi Mitake wrote:
>> There are a lot of lock instances with same names (e.g. port_lock).
>> This patch series add __FILE__ and __LINE__ to lockdep_map,
>> and these will be used for trace lock events.
>>
>> Example use from perf lock map:
>>
>> | 0xffffea0004c992b8: __pte_lockptr(page) (src: include/linux/mm.h, line: 952)
>> | 0xffffea0004b112b8: __pte_lockptr(page) (src: include/linux/mm.h, line: 952)
>> | 0xffffea0004a3f2b8: __pte_lockptr(page) (src: include/linux/mm.h, line: 952)
>> | 0xffffea0004cd5228: __pte_lockptr(page) (src: include/linux/mm.h, line: 952)
>> | 0xffff8800b91e2b28:&sb->s_type->i_lock_key (src: fs/inode.c, line: 166)
>> | 0xffff8800bb9d7ae0: key (src: kernel/wait.c, line: 16)
>> | 0xffff8800aa07dae0:&dentry->d_lock (src: fs/dcache.c, line: 944)
>> | 0xffff8800b07fbae0:&dentry->d_lock (src: fs/dcache.c, line: 944)
>> | 0xffff8800b07f3ae0:&dentry->d_lock (src: fs/dcache.c, line: 944)
>> | 0xffff8800bf15fae0:&sighand->siglock (src: kernel/fork.c, line: 1490)
>> | 0xffff8800b90f7ae0:&dentry->d_lock (src: fs/dcache.c, line: 944)
>> | ...
>>
>> (This output of perf lock map is produced by my local version,
>> I'll send this later.)
>>
>> And sadly, as Peter Zijlstra predicted, this produces certain overhead.
>>
>> Before appling this series:
>> | % sudo ./perf lock rec perf bench sched messaging
>> | # Running sched/messaging benchmark...
>> | # 20 sender and receiver processes per group
>> | # 10 groups == 400 processes run
>> |
>> | Total time: 3.834 [sec]
>> After:
>> sudo ./perf lock rec perf bench sched messaging
>> | # Running sched/messaging benchmark...
>> | # 20 sender and receiver processes per group
>> | # 10 groups == 400 processes run
>> |
>> | Total time: 5.415 [sec]
>> | [ perf record: Woken up 0 times to write data ]
>> | [ perf record: Captured and wrote 53.512 MB perf.data (~2337993 samples) ]
>>
>> But raw exec of perf bench sched messaging is this:
>> | % perf bench sched messaging
>> | # Running sched/messaging benchmark...
>> | # 20 sender and receiver processes per group
>> | # 10 groups == 400 processes run
>> |
>> | Total time: 0.498 [sec]
>>
>> Tracing lock events already produces amount of overhead.
>> I think the overhead produced by this series is not a fatal problem,
>> radically optimization is required...
>
> Right, these patches look OK, for the tracing overhead, you could
> possibly hash the file:line into a u64 and reduce the tracepoint size,
> that should improve the situation I tihnk, because I seem to remember
> the only thing that really matters for speed is the size of things.
>
>
Thanks for your opinion, Peter.
I'll work on reducing size of events later. Hashing is a good idea.
I think indexing is also way to reduce size.
And I want lockdep_map to have another thing, type of lock.
For example, mutex and spinlock has completely different acquired time
and attributes,
so I want to separate these things. If lockdep_map has member
to express type, things will be easy.
How do you think?
next prev parent reply other threads:[~2010-01-16 13:01 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-16 3:28 [PATCH 1/2] perf: Add util/include/linuxhash.h to include hash.h of kernel Hitoshi Mitake
2009-12-16 3:28 ` [PATCH 2/2] perf lock: Fix output of tracing lock events Hitoshi Mitake
2009-12-16 8:19 ` [tip:perf/lock] " tip-bot for Hitoshi Mitake
2009-12-17 8:50 ` [PATCH 2/2] " Ingo Molnar
2009-12-17 9:24 ` Peter Zijlstra
2009-12-17 10:09 ` Ingo Molnar
2009-12-17 10:26 ` Peter Zijlstra
2009-12-17 10:51 ` Ingo Molnar
2009-12-26 13:43 ` Hitoshi Mitake
2009-12-28 10:01 ` Peter Zijlstra
2009-12-31 13:24 ` Hitoshi Mitake
2010-01-07 10:38 ` Hitoshi Mitake
2010-01-07 10:39 ` [PATCH 0/5] lockdep: Add information of file and line to lockdep_map Hitoshi Mitake
2010-01-13 9:52 ` Peter Zijlstra
2010-01-13 10:09 ` Ingo Molnar
2010-01-16 13:01 ` Hitoshi Mitake [this message]
2010-01-18 7:20 ` Peter Zijlstra
2010-01-26 5:56 ` [PATCH] Add type of locks to lock trace events Hitoshi Mitake
2010-01-28 10:21 ` Peter Zijlstra
2010-01-29 17:29 ` Frederic Weisbecker
2010-01-29 17:41 ` Peter Zijlstra
2010-01-29 22:12 ` Frederic Weisbecker
2010-02-24 9:02 ` [PATCH] Separate lock events with types Hitoshi Mitake
2010-03-26 23:33 ` Frederic Weisbecker
2010-04-05 10:37 ` Hitoshi Mitake
2010-04-06 8:26 ` Peter Zijlstra
2010-04-06 9:44 ` Frederic Weisbecker
2010-01-07 10:39 ` [PATCH 1/5] lockdep: Add file and line to initialize sequence of spin and rw lock Hitoshi Mitake
2010-01-07 10:39 ` [PATCH 2/5] lockdep: Add file and line to initialize sequence of rwsem Hitoshi Mitake
2010-01-07 10:39 ` [PATCH 3/5] " Hitoshi Mitake
2010-01-07 10:39 ` [PATCH 4/5] lockdep: Add file and line to initialize sequence of mutex Hitoshi Mitake
2010-01-07 10:39 ` [PATCH 5/5] lockdep: Fix the way to initialize class_mutex for information of file and line Hitoshi Mitake
2010-01-13 10:00 ` Ingo Molnar
2010-01-13 23:17 ` Greg KH
2010-01-13 23:19 ` Greg KH
2010-01-16 12:55 ` Hitoshi Mitake
2009-12-16 8:18 ` [tip:perf/lock] perf: Add util/include/linuxhash.h to include hash.h of kernel tip-bot for Hitoshi Mitake
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