Re: Unified tracing buffer

[Masami Hiramatsu]

Peter Zijlstra wrote:
> On Mon, 2008-09-22 at 09:29 -0700, Martin Bligh wrote:
>>>> In conjunction with the previous email on this thread
>>>> (http://lkml.org/lkml/2008/9/22/160), may I suggest
>>>> the equivalent interfaces in -mm tree (2.6.27-rc5-mm1) to be:
>>>>
>>>> relay_printk(<some struct with default filenames/pathnames>, <string>,
>>>> ....) ;
>>>> relay_dump(<some struct with default filenames/pathnames>, <binary
>>>> data>);
>>>> and
>>>> relay_cleanup_all(<the struct name>); - Single interface that cleans up
>>>> all files/directories/output data created under a logical entity.
>>> Dude, relayfs is such a bad performing mess that extending it seems like
>>> a bad idea. Better to write something new and delete everything relayfs
>>> related.
>> There did seem to be pretty universal agreement that we'd rather not
>> use relayfs.
>>
>>> Also, it seems prudent to separate the ring-buffer implementation from
>>> the event encoding/decoding facilities.
>> Right - in conversation I had with Mathieu later, he suggested cleaning up
>> relayfs - I fear this will delay us far too long, and get bogged down.
>> If we can get one clean circular buffer implementation, then both
>> relayfs and the tracing could share that common solution,
> 
> Currently only blktrace and kvmtrace use relayfs, and I've heard people
> talk about converting both to use lttng/ftrace infrastructure. At which
> point relayfs is orphaned and ready for removal.

Hi Peter,
Systemtap is still a heavy user of relayfs. :-)
Anyway, if new buffering mechanism is enough for us, I think
we're happy to move on it.

Thank you,

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@xxxxxxxxxx

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/