Messages in this thread | | | Date | Wed, 25 Mar 2009 15:25:41 +0800 | From | Li Zefan <> | Subject | Re: [RFC][PATCH] blktrace: fix original blktrace |
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Jens Axboe wrote: > On Wed, Mar 25 2009, Li Zefan wrote: >> I'm wondering what we are going to do with the original blktrace which >> is using relay and is used via ioctl. >> >> The problem is currently it's totally broken. You can use ftrace to see >> the output of blktrace, but user-space blktrace is unusable. >> >> With this patch, both ioctl and ftrace can be used, but of course you >> can't use both of them at the same time. > > Even if ftrace was as fast as storing huge amounts of data as blktrace, > it's still of utmost importance that nothing is broken there. There are
agreed
> people actually USING this tracing to do real work, it's not a > playground. >
and we are using blktrace to test the cgroup-based io controller
> I appreciate the efforts to unify and improve our tracing, but we must > not be breaking blktrace along the way. Otherwise the whole thing goes
this patch fixes it.
it's broken by "blktrace: add ftrace plugin" (c71a896154119f4ca9e89d6078f5f63ad60ef199)
@@ -131,13 +162,14 @@ static void __blk_add_trace() - if (unlikely(bt->trace_state != Blktrace_running)) + if (unlikely(bt->trace_state != Blktrace_running || !blk_tracer_enabled)) return;
> back to block/blktrace.c, period. >
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