lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 22 Oct 2015 11:06:32 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Alexei Starovoitov <ast@...mgrid.com>
Cc:	pi3orama <pi3orama@....com>, "Wangnan (F)" <wangnan0@...wei.com>,
	xiakaixu <xiakaixu@...wei.com>, davem@...emloft.net,
	acme@...nel.org, mingo@...hat.com, masami.hiramatsu.pt@...achi.com,
	jolsa@...nel.org, daniel@...earbox.net,
	linux-kernel@...r.kernel.org, hekuang@...wei.com,
	netdev@...r.kernel.org
Subject: Re: [PATCH V5 1/1] bpf: control events stored in PERF_EVENT_ARRAY
 maps trace data output when perf sampling

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?
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists