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From: Alexei Starovoitov <ast@plumgrid.com>
To: He Kuang <hekuang@huawei.com>,
	ast@kernel.org, davem@davemloft.net, daniel@iogearbox.net,
	mingo@kernel.org, rostedt@goodmis.org, xiakaixu@huawei.com
Cc: wangnan0@huawei.com, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] bpf: Add new bpf map type for timer
Date: Wed, 21 Oct 2015 12:53:33 -0700	[thread overview]
Message-ID: <5627ED3D.5080004@plumgrid.com> (raw)
In-Reply-To: <562762B8.5060706@huawei.com>

On 10/21/15 3:02 AM, He Kuang wrote:
> Here's a hypothetical scenario to illustrate the use of timer map.
>
> A video frame is updated between frame_refresh_start() and
> frame_refresh_end(), in most cases, the interval between these two
> functions is less than 40ms, but occasionally over 200ms.
>
> We can set a timer which alarm after the frame_refresh_start() has
> been executed 42ms(slightly larger than 40ms) and destory this timer
> if frame_refresh_end() is called. So, for most cases, the timer is not
> triggered, this can significantly reduce the amount of trace data.

As a feature it sounds useful, but implementation is not acceptable.
You cannot have one callback stub for all users of this feature.


      parent reply	other threads:[~2015-10-21 19:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-19  5:34 [RFC PATCH] bpf: Add new bpf map type for timer He Kuang
2015-10-19  6:30 ` [RFC PATCH] bpf: bpf_timer_callback() can be static kbuild test robot
2015-10-19  6:30 ` [RFC PATCH] bpf: Add new bpf map type for timer kbuild test robot
2015-10-21 10:02 ` He Kuang
2015-10-21 10:20   ` Ingo Molnar
2015-10-21 10:38     ` Wangnan (F)
2015-10-21 10:47       ` Ingo Molnar
2015-10-21 19:53   ` Alexei Starovoitov [this message]

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