Commit Graph

6 Commits

Author SHA1 Message Date
Brad Fitzpatrick 9f1b02699a tstime: add RandomDurationBetween helper
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-01-21 07:54:14 -08:00
Josh Bleecher Snyder aa9d7f4665 tstime: add Parse3339B, for byte slices
Use go4.org/mem for memory safety.
A slight performance hit, but a huge performance win
for clients who start with a []byte.
The perf hit is due largely to the MapHash call, which adds ~25ns.
That is necessary to keep the fast path allocation-free.

name                     old time/op    new time/op    delta
GoParse3339/Z-8             281ns ± 1%     283ns ± 2%     ~     (p=0.366 n=9+9)
GoParse3339/TZ-8            509ns ± 0%     510ns ± 1%     ~     (p=0.059 n=9+9)
GoParse3339InLocation-8     330ns ± 1%     330ns ± 0%     ~     (p=0.802 n=10+6)
Parse3339/Z-8              69.3ns ± 1%    74.4ns ± 1%   +7.45%  (p=0.000 n=9+10)
Parse3339/TZ-8              110ns ± 1%     140ns ± 3%  +27.42%  (p=0.000 n=9+10)
ParseInt-8                 8.20ns ± 1%    8.17ns ± 1%     ~     (p=0.452 n=9+9)

name                     old alloc/op   new alloc/op   delta
GoParse3339/Z-8             0.00B          0.00B          ~     (all equal)
GoParse3339/TZ-8             160B ± 0%      160B ± 0%     ~     (all equal)
GoParse3339InLocation-8     0.00B          0.00B          ~     (all equal)
Parse3339/Z-8               0.00B          0.00B          ~     (all equal)
Parse3339/TZ-8              0.00B          0.00B          ~     (all equal)

name                     old allocs/op  new allocs/op  delta
GoParse3339/Z-8              0.00           0.00          ~     (all equal)
GoParse3339/TZ-8             3.00 ± 0%      3.00 ± 0%     ~     (all equal)
GoParse3339InLocation-8      0.00           0.00          ~     (all equal)
Parse3339/Z-8                0.00           0.00          ~     (all equal)
Parse3339/TZ-8               0.00           0.00          ~     (all equal)


Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2020-11-19 14:47:11 -08:00
David Anderson b925e18f70 tstime: hand-implement parseInt for specific needs of rfc3339 parsing.
Makes parsing 4.6x faster.

name         old time/op  new time/op  delta
ParseInt-12  32.1ns ± 1%   6.9ns ± 2%  -78.55%  (p=0.000 n=10+9)

Signed-off-by: David Anderson <danderson@tailscale.com>
2020-04-14 12:36:55 -07:00
Brad Fitzpatrick 71d6738333 tstime: change an Errorf+return to Fatalf in subtest
Forgot to git add this during review. Fail.
2020-04-06 08:20:15 -07:00
Brad Fitzpatrick febdac0499 tstime: write Parse3339 parse that doesn't use time.Parse
It doesn't allocate and it's half the time of time.Parse (which
allocates), and 2/3rds the time of time.ParseInLocation (which
doesn't).

Go with a UTC time:

BenchmarkGoParse3339/Z-8                 2200995               534 ns/op               0 B/op          0 allocs/op
BenchmarkGoParse3339/Z-8                 2254816               554 ns/op               0 B/op          0 allocs/op
BenchmarkGoParse3339/Z-8                 2159504               522 ns/op               0 B/op          0 allocs/op

Go allocates with a "-08:00" suffix instead of ending in "Z":

BenchmarkGoParse3339/TZ-8                1276491               884 ns/op             144 B/op          3 allocs/op
BenchmarkGoParse3339/TZ-8                1355858               942 ns/op             144 B/op          3 allocs/op
BenchmarkGoParse3339/TZ-8                1385484               911 ns/op             144 B/op          3 allocs/op

Go doesn't allocate if you use time.ParseInLocation, but then you need
to parse the string to find the location anyway, so might as well go
all the way (below).

BenchmarkGoParse3339InLocation-8         1912254               597 ns/op               0 B/op          0 allocs/op
BenchmarkGoParse3339InLocation-8         1980043               612 ns/op               0 B/op          0 allocs/op
BenchmarkGoParse3339InLocation-8         1891366               612 ns/op               0 B/op          0 allocs/op

Parsing RFC3339 ourselves, UTC:

BenchmarkParse3339/Z-8                   3889220               307 ns/op               0 B/op          0 allocs/op
BenchmarkParse3339/Z-8                   3718500               309 ns/op               0 B/op          0 allocs/op
BenchmarkParse3339/Z-8                   3621231               303 ns/op               0 B/op          0 allocs/op

Parsing RFC3339 ourselves, with timezone (w/ *time.Location fetched
from sync.Map)

BenchmarkParse3339/TZ-8                  3019612               418 ns/op               0 B/op          0 allocs/op
BenchmarkParse3339/TZ-8                  2921618               401 ns/op               0 B/op          0 allocs/op
BenchmarkParse3339/TZ-8                  3031671               408 ns/op               0 B/op          0 allocs/op

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2020-04-06 08:19:17 -07:00
Brad Fitzpatrick d503dee6f1 tstime: add new package for time utilities, starting with Parse3339
Go's time.Parse always allocates a FixedZone for time strings not in
UTC (ending in "Z"). This avoids that allocation, at the cost of
adding a cache.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2020-04-05 20:05:49 -07:00