From: Derrick Stolee <stolee@gmail.com>
To: Jeff King <peff@peff.net>
Cc: "brian m. carlson" <sandals@crustytoothpaste.net>,
"Jonathan Nieder" <jrnieder@gmail.com>,
"Paul Smith" <paul@mad-scientist.net>,
git@vger.kernel.org, "Duy Nguyen" <pclouds@gmail.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [ANNOUNCE] Git v2.19.0-rc0
Date: Thu, 23 Aug 2018 16:59:27 -0400 [thread overview]
Message-ID: <4b0168ee-4826-1f14-fc83-04c4cec18687@gmail.com> (raw)
In-Reply-To: <20180823185317.GA12534@sigill.intra.peff.net>
On 8/23/2018 2:53 PM, Jeff King wrote:
> On Thu, Aug 23, 2018 at 06:26:58AM -0400, Derrick Stolee wrote:
>
>>> I think you can safely
>>> ignore the rest of it if you are otherwise occupied. Even if v2.19 ships
>>> without some mitigation, I don't know that it's all that big a deal,
>>> given the numbers I generated (which for some reason are less dramatic
>>> than Stolee's).
>> My numbers may be more dramatic because my Linux environment is a virtual
>> machine.
> If you have a chance, can you run p0001 on my patch (compared to
> 2.19-rc0, or to both v2.18 and v2.19-rc0)? It would be nice to double
> check that it really is fixing the problem you saw.
Sure. Note: I had to create a new Linux VM on a different machine
between Tuesday and today, so the absolute numbers are different.
Using git/git:
Test v2.18.0 v2.19.0-rc0 HEAD
-------------------------------------------------------------------------
0001.2: 3.10(3.02+0.08) 3.27(3.17+0.09) +5.5% 3.14(3.02+0.11) +1.3%
Using torvalds/linux:
Test v2.18.0 v2.19.0-rc0 HEAD
------------------------------------------------------------------------------
0001.2: 56.08(45.91+1.50) 56.60(46.62+1.50) +0.9% 54.61(45.47+1.46) -2.6%
Now here is where I get on my soapbox (and create a TODO for myself
later). I ran the above with GIT_PERF_REPEAT_COUNT=10, which intuitively
suggests that the results should be _more_ accurate than the default of
3. However, I then remember that we only report the *minimum* time from
all the runs, which is likely to select an outlier from the
distribution. To test this, I ran a few tests manually and found the
variation between runs to be larger than 3%.
When I choose my own metrics for performance tests, I like to run at
least 10 runs, remove the largest AND smallest runs from the samples,
and then take the average. I did this manually for 'git rev-list --all
--objects' on git/git and got the following results:
v2.18.0 v2.19.0-rc0 HEAD
--------------------------------
3.126 s 3.308 s 3.170 s
For full disclosure, here is a full table including all samples:
| | v2.18.0 | v2.19.0-rc0 | HEAD |
|------|---------|-------------|---------|
| | 4.58 | 3.302 | 3.239 |
| | 3.13 | 3.337 | 3.133 |
| | 3.213 | 3.291 | 3.159 |
| | 3.219 | 3.318 | 3.131 |
| | 3.077 | 3.302 | 3.163 |
| | 3.074 | 3.328 | 3.119 |
| | 3.022 | 3.277 | 3.125 |
| | 3.083 | 3.259 | 3.203 |
| | 3.057 | 3.311 | 3.223 |
| | 3.155 | 3.413 | 3.225 |
| Max | 4.58 | 3.413 | 3.239 |
| Min | 3.022 | 3.259 | 3.119 |
| Avg* | 3.126 | 3.30825 | 3.17025 |
(Note that the largest one was the first run, on v2.18.0, which is due
to a cold disk.)
I just kicked off a script that will run this test on the Linux repo
while I drive home. I'll be able to report a similar table of data easily.
My TODO is to consider aggregating the data this way (or with a median)
instead of reporting the minimum.
Thanks,
-Stolee
next prev parent reply other threads:[~2018-08-23 20:59 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-20 22:13 [ANNOUNCE] Git v2.19.0-rc0 Junio C Hamano
2018-08-20 22:41 ` Stefan Beller
2018-08-20 23:39 ` Jonathan Nieder
2018-08-21 0:27 ` Jonathan Nieder
2018-08-21 0:46 ` Stefan Beller
2018-08-21 20:41 ` Derrick Stolee
2018-08-21 21:29 ` Jeff King
2018-08-22 0:48 ` brian m. carlson
2018-08-22 3:03 ` Jeff King
2018-08-22 3:36 ` Jeff King
2018-08-22 11:11 ` Derrick Stolee
2018-08-22 5:36 ` brian m. carlson
2018-08-22 6:07 ` Jeff King
2018-08-22 7:39 ` Ævar Arnfjörð Bjarmason
2018-08-22 11:14 ` Derrick Stolee
2018-08-22 15:17 ` Jeff King
2018-08-22 16:08 ` Duy Nguyen
2018-08-22 16:14 ` Duy Nguyen
2018-08-22 16:26 ` Jeff King
2018-08-22 16:49 ` Derrick Stolee
2018-08-22 16:58 ` Duy Nguyen
2018-08-22 17:04 ` Derrick Stolee
2018-08-22 16:59 ` Jeff King
2018-08-22 17:02 ` Junio C Hamano
2018-08-22 15:14 ` Jeff King
2018-08-22 14:28 ` Derrick Stolee
2018-08-22 15:24 ` Jeff King
2018-08-22 12:42 ` Paul Smith
2018-08-22 15:23 ` Jeff King
2018-08-23 1:23 ` Jonathan Nieder
2018-08-23 2:16 ` Jeff King
2018-08-23 2:27 ` Jonathan Nieder
2018-08-23 5:02 ` Jeff King
2018-08-23 5:09 ` brian m. carlson
2018-08-23 5:10 ` Jonathan Nieder
2018-08-23 13:20 ` Junio C Hamano
2018-08-23 16:31 ` wide t/perf output, was " Jeff King
2018-08-23 3:47 ` brian m. carlson
2018-08-23 5:04 ` Jeff King
2018-08-23 10:26 ` Derrick Stolee
2018-08-23 13:16 ` Junio C Hamano
2018-08-23 16:14 ` Jeff King
2018-08-23 23:30 ` Jacob Keller
2018-08-23 23:40 ` Jeff King
2018-08-24 0:06 ` Jeff King
2018-08-24 0:16 ` Jeff King
2018-08-24 2:48 ` Jacob Keller
2018-08-24 2:59 ` Jeff King
2018-08-24 6:45 ` Jeff King
2018-08-24 11:04 ` Derrick Stolee
2018-08-27 19:36 ` Junio C Hamano
2018-08-23 18:53 ` Jeff King
2018-08-23 20:59 ` Derrick Stolee [this message]
2018-08-24 6:56 ` Jeff King
2018-08-24 7:57 ` Ævar Arnfjörð Bjarmason
2018-08-24 16:45 ` Derrick Stolee
2018-08-25 8:26 ` Jeff King
2018-09-02 18:53 ` Kaartic Sivaraam
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