From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <ast@plumgrid.com>
Cc: pi3orama <pi3orama@163.com>, "Wangnan (F)" <wangnan0@huawei.com>,
xiakaixu <xiakaixu@huawei.com>,
davem@davemloft.net, acme@kernel.org, mingo@redhat.com,
masami.hiramatsu.pt@hitachi.com, jolsa@kernel.org,
daniel@iogearbox.net, linux-kernel@vger.kernel.org,
hekuang@huawei.com, netdev@vger.kernel.org
Subject: Re: [PATCH V5 1/1] bpf: control events stored in PERF_EVENT_ARRAY maps trace data output when perf sampling
Date: Thu, 22 Oct 2015 11:06:32 +0200 [thread overview]
Message-ID: <20151022090632.GK2508@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <56280175.8060404@plumgrid.com>
On Wed, Oct 21, 2015 at 02:19:49PM -0700, Alexei Starovoitov wrote:
> >Urgh, that's still horridly inconsistent. Can we please come up with a
> >consistent interface to perf?
> My suggestion was to do ioctl(enable/disable) of events from userspace
> after receiving notification from kernel via my bpf_perf_event_output()
> helper.
> Wangnan's argument was that display refresh happens often and it's fast,
> so the time taken by user space to enable events on all cpus is too
> slow and ioctl does ipi and disturbs other cpus even more.
> So soft_disable done by the program to enable/disable particular events
> on all cpus kinda makes sense.
And this all makes me think I still have no clue what you're all trying
to do here.
Who cares about display updates and why. And why should there be an
active userspace part to eBPF programs?
next prev parent reply other threads:[~2015-10-22 9:06 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-20 7:22 [PATCH V5 0/1] bpf: control events stored in PERF_EVENT_ARRAY maps trace data output when perf sampling Kaixu Xia
2015-10-20 7:22 ` [PATCH V5 1/1] " Kaixu Xia
2015-10-20 22:53 ` Alexei Starovoitov
2015-10-21 9:12 ` Peter Zijlstra
2015-10-21 10:31 ` xiakaixu
2015-10-21 11:33 ` Peter Zijlstra
2015-10-21 11:49 ` Wangnan (F)
2015-10-21 12:17 ` Peter Zijlstra
2015-10-21 13:42 ` Wangnan (F)
2015-10-21 13:49 ` Peter Zijlstra
2015-10-21 14:01 ` pi3orama
2015-10-21 14:09 ` Peter Zijlstra
2015-10-21 15:06 ` pi3orama
2015-10-21 16:57 ` Peter Zijlstra
2015-10-21 21:19 ` Alexei Starovoitov
2015-10-22 9:06 ` Peter Zijlstra [this message]
2015-10-22 10:28 ` Wangnan (F)
2015-10-23 12:52 ` Peter Zijlstra
2015-10-23 15:12 ` Peter Zijlstra
2015-10-27 6:43 ` xiakaixu
2015-10-22 2:46 ` Wangnan (F)
2015-10-22 7:39 ` Ingo Molnar
2015-10-22 7:51 ` Wangnan (F)
2015-10-22 9:24 ` Peter Zijlstra
2015-10-22 1:56 ` Wangnan (F)
2015-10-22 3:09 ` Alexei Starovoitov
2015-10-22 3:12 ` Wangnan (F)
2015-10-22 3:26 ` Alexei Starovoitov
2015-10-22 9:49 ` Peter Zijlstra
2015-10-21 11:34 ` Wangnan (F)
2015-10-21 11:56 ` Peter Zijlstra
2015-10-21 12:03 ` Wangnan (F)
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