x/build/env/windows: disable Windows Defender in windows-amd64-2016

[bradfitz]

The Windows Defender (new in Windows Server 2016) is making filesystem access super slow on our windows-amd64-2016 builder.

Instead of a handful of seconds to extract the source tarball, it takes about a minute on windows-amd64-2016.

We need to disable PowerShell somehow programmatically from the buildlet, or change our image.

/cc @johnsonj

[bradfitz]

FTR,

bradfitz@gdev:~/src/golang.org/x/build/cmd$ gomote create windows-amd64-2016
user-bradfitz-windows-amd64-2016-0
bradfitz@gdev:~/src/golang.org/x/build/cmd$ gomote run -system user-bradfitz-windows-amd64-2016-0 sc query WinDefend

SERVICE_NAME: WinDefend 
        TYPE               : 10  WIN32_OWN_PROCESS  
        STATE              : 4  RUNNING 
                                (STOPPABLE, NOT_PAUSABLE, ACCEPTS_SHUTDOWN)
        WIN32_EXIT_CODE    : 0  (0x0)
        SERVICE_EXIT_CODE  : 0  (0x0)
        CHECKPOINT         : 0x0
        WAIT_HINT          : 0x0

bradfitz@gdev:~/src/golang.org/x/build/cmd$ time gomote push user-bradfitz-windows-amd64-2016-0
2018/06/25 21:05:21 installing go1.4
2018/06/25 21:05:42 Remote doesn't have "src/math/unsafe.go"
2018/06/25 21:05:42 Remote doesn't have "test/fixedbugs/issue6703o.go"
2018/06/25 21:05:42 Remote doesn't have "misc/nacl/go_nacl_386_exec"
2018/06/25 21:05:42 Remote doesn't have "src/debug/gosym/pclinetest.h"
2018/06/25 21:05:42 Remote doesn't have "src/runtime/defs_netbsd.go"
2018/06/25 21:05:42 Remote doesn't have 7982 files (only showed 5).
2018/06/25 21:05:42 Remote lacks a VERSION file; sending a fake one
2018/06/25 21:05:53 Uploading 7983 new/changed files; 145856045 byte .tar.gz

real    1m18.972s
user    0m11.612s
sys     0m0.580s
bradfitz@gdev:~/src/golang.org/x/build/cmd$ time gomote rm user-bradfitz-windows-amd64-2016-0 .

real    0m2.559s
user    0m0.104s
sys     0m0.012s

That 1m18.982s is pretty slow.

Unfortunately the buildlet is running as user gopher (not admin) and the admin has no password set so we can't use runas to sc stop it.

So updating the image is our best option. Then we can re-benchmark it with the above.

[bradfitz]

Also FTR,

SELECT Builder, AVG(Seconds) as Sec, COUNT(*) FROM builds.Spans WHERE Event='write_go_src_tar' AND Error='' AND StartTime > TIMESTAMP_SUB(CURRENT_TIMESTAMP(), INTERVAL 500 HOUR) GROUP BY 1 ORDER BY Sec DESC;

#	Builder	Seconds	Count
1	dragonfly-amd64	185.60650053108293	229
2	linux-mips	152.23976293918628	220
3	plan9-arm	80.30161213704082	245
4	freebsd-arm-paulzhol	63.06639745541143	175
5	windows-amd64-2016	55.55313342421522	618
6	linux-arm	49.075175881510845	231
7	linux-arm-nativemake	48.70805966784979	233
8	linux-arm64-packet	19.515660791081444	221
9	android-386-emulator	18.119463975340423	235
10	darwin-arm64-a1549ios	16.899542428412843	218
11	darwin-arm-a1428ios	16.739108357539738	239
12	android-amd64-emulator	16.54923103103448	232
13	android-arm-wiko-fever	15.080117587781658	229
14	android-arm64-wiko-fever	14.462792876952378	231
15	plan9-amd64-9front	14.405663703632353	68
16	solaris-amd64-oraclerel	12.100369053424782	226
17	linux-mipsle	10.584515092049774	221
18	plan9-386	9.966798731117123	222
19	darwin-amd64-10_12	8.794949175008892	225
20	darwin-amd64-race	8.605581733506607	227
21	darwin-amd64-10_10	8.154243777534242	219
22	darwin-386-10_11	7.946001849290908	220
23	darwin-amd64-10_11	7.703967139495968	248
24	windows-amd64-2008	7.034785014407078	226
25	openbsd-386-62	7.010430919705883	221
26	windows-amd64-race	6.797259301486726	226
27	windows-386-2008	6.646885542157986	576
28	solaris-amd64-smartosbuildlet	6.024883029986425	221
29	windows-amd64-2012	5.337799377800866	231
30	linux-s390x-ibm	4.947826236703196	219
31	linux-ppc64le-buildlet	4.35824075608889	225
32	linux-ppc64-buildlet	4.307531873781248	224
33	openbsd-amd64-62	3.0256817755499097	551
34	netbsd-amd64-8_0	2.956358088454129	218
35	freebsd-386-10_3	2.3237422244598203	224
36	freebsd-amd64-10_3	2.294154283222727	220
37	freebsd-amd64-race	2.269509212908676	219
38	freebsd-386-11_1	2.2659248075675666	222
39	freebsd-amd64-11_1	2.102135369425992	554
40	linux-arm-arm5spacemonkey	1.1791402133607305	219
41	misc-compile-nacl	1.108447655222222	90
42	linux-amd64-nocgo	1.0897813647031966	219
43	misc-compile-ppc	1.080169373228659	328
44	linux-amd64-ssacheck	1.0798409478082194	219
45	linux-amd64-sid	1.0794736670136982	219
46	nacl-386	1.0792323511771218	542
47	js-wasm	1.0791127955347828	230
48	linux-amd64-race	1.078254141806331	537
49	nacl-amd64p32	1.0779594923314915	543
50	misc-compile-freebsd	1.077641247359756	328

[johnsonj]

Uninstalling Windows Defender looks like a big speedup. CL incoming.

Fresh instance, n1-standard-4, gomote push:

.. clipped by buffer
2018/07/02 09:58:00 Uploading 7171 new/changed files; 20499864 byte .tar.gz
     
real    0m33.565s
user    0m3.976s
sys     0m0.508s

gomote put14

real	0m3.477s
user	0m0.008s
sys	0m0.008s

[gopherbot]

Change https://golang.org/cl/121937 mentions this issue: env/windows: disable windows defender on builders

[bradfitz]

Yup, it went from about 56 seconds to 6.8:

2018/07/02 19:38:04 SERIAL: 2018/07/02 19:38:03 extracted tarball into C:\workdir\go: 7908 files, 980 dirs (6.8310531s)