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From: "H. Peter Anvin" <hpa@zytor.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <vda.linux@googlemail.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Frederic Weisbecker <fweisbec@gmail.com>, X86 ML <x86@kernel.org>,
	Alexei Starovoitov <ast@plumgrid.com>,
	Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH 4/5] x86: entry_64.S: always allocate complete "struct pt_regs"
Date: Sat, 02 Aug 2014 14:23:04 -0700	[thread overview]
Message-ID: <cd1d542c-ceb9-4c91-aaf9-de702824803a@email.android.com> (raw)
In-Reply-To: <CALCETrU2ZUKorqUzFZUJ7TRSUL9fS9yBT+SiSH_Zsz6bHcE36A@mail.gmail.com>

It would be nice to automate running a T-test on it.

On August 2, 2014 2:14:50 PM PDT, Andy Lutomirski <luto@amacapital.net> wrote:
>On Fri, Aug 1, 2014 at 3:13 PM, H. Peter Anvin <hpa@zytor.com> wrote:
>> On 08/01/2014 03:11 PM, Denys Vlasenko wrote:
>>>>
>>>> Could you please try to see if there is a measurable change in the
>>>> latency of a trivial syscall?
>>>
>>> Will do.
>>> Something along the lines of "how long does it take to execute two
>>> gazillions of getppid()?"
>>>
>>
>> Something like that, yes, but you have to run enough data points so
>you
>> can determine if the difference is statistically significant or just
>noise.
>
>Denys, if you want to avoid five minutes of programming, you can build
>this:
>
>https://gitorious.org/linux-test-utils/linux-clock-tests/
>
>and run timing_test_64 10 getpid
>
>It doesn't do real statistics, but it seems to get quite stable
>results.
>
>--Andy

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.

  reply	other threads:[~2014-08-02 21:23 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-01 14:48 [PATCH 1/5] x86: entry_64.S: delete unused code Denys Vlasenko
2014-08-01 14:48 ` [PATCH 2/5] x86: open-code register save/restore in trace_hardirqs thunks Denys Vlasenko
2014-08-01 14:48 ` [PATCH 3/5] x86: entry_64.S: fold SAVE_ARGS_IRQ macro into its sole user Denys Vlasenko
2014-08-01 18:30   ` Frederic Weisbecker
2014-08-01 14:48 ` [PATCH 4/5] x86: entry_64.S: always allocate complete "struct pt_regs" Denys Vlasenko
2014-08-01 17:04   ` Andy Lutomirski
2014-08-04 14:28     ` Denys Vlasenko
2014-08-04 14:47       ` Oleg Nesterov
2014-08-04 15:34         ` Oleg Nesterov
2014-08-04 21:03       ` Andy Lutomirski
2014-08-04 21:23         ` Borislav Petkov
2014-08-05 10:35         ` Denys Vlasenko
2014-08-05 14:53           ` Andy Lutomirski
2014-08-05 15:17             ` Denys Vlasenko
2014-08-05 23:02               ` Andy Lutomirski
2014-08-07  9:54             ` Denys Vlasenko
2014-08-01 18:09   ` Alexei Starovoitov
2014-08-01 18:30   ` Oleg Nesterov
2014-08-01 18:35   ` H. Peter Anvin
2014-08-01 22:11     ` Denys Vlasenko
2014-08-01 22:13       ` H. Peter Anvin
2014-08-02 21:14         ` Andy Lutomirski
2014-08-02 21:23           ` H. Peter Anvin [this message]
2014-08-02 21:38             ` Andy Lutomirski
2014-08-01 22:52   ` Frederic Weisbecker
2014-08-01 23:19   ` Frederic Weisbecker
2014-08-04  3:03     ` Denys Vlasenko
2014-08-04  7:57       ` Borislav Petkov
2014-08-11  0:46       ` Frederic Weisbecker
2014-08-11  8:40         ` Jan Beulich
2014-08-11  9:07           ` Andy Lutomirski
2014-08-11  9:31             ` Jan Beulich
2014-08-11 13:26           ` Denys Vlasenko
2014-08-11 14:17             ` Jan Beulich
2014-08-11 14:53               ` H. Peter Anvin
2014-08-11 15:08                 ` Jan Beulich
2014-08-11 15:13                   ` H. Peter Anvin
2014-08-12  9:31                     ` Denys Vlasenko
2014-08-12  9:50                       ` Jan Beulich
2014-08-01 14:48 ` [PATCH 5/5] x86: mass removal of ARGOFFSET Denys Vlasenko
2014-08-01 18:00 ` [PATCH 1/5] x86: entry_64.S: delete unused code Frederic Weisbecker

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