Use direct cache in index reader for symbol values

[yeya24]

Signed-off-by: Ben Ye yb532204897@gmail.com

• I added CHANGELOG entry for this change.
• Change is not relevant to the end user.

Changes

Apply the same improvement as the upstream Prometheus pr prometheus/prometheus#8265.

The benchmark result is great comparing to the current master.

name                                                             old time/op    new time/op    delta
TelemeterRealData_Series/alerts2w/01EPXBGA0413QZMTF4XQ0M4Q3E        16.7s ± 0%     11.8s ± 0%  -29.31%
TelemeterRealData_Series/alerts15s/01EPXBGA0413QZMTF4XQ0M4Q3E       3.95s ± 0%     3.93s ± 0%   -0.53%
TelemeterRealData_Series/subssyncs2w/01EPXBGA0413QZMTF4XQ0M4Q3E     2.44s ± 0%     1.18s ± 0%  -51.63%
TelemeterRealData_Series/subs2w/01EPXBGA0413QZMTF4XQ0M4Q3E          14.3s ± 0%      6.3s ± 0%  -56.04%
TelemeterRealData_Series/subs15s/01EPXBGA0413QZMTF4XQ0M4Q3E         2.07s ± 0%     2.11s ± 0%   +2.00%

name                                                             old alloc/op   new alloc/op   delta
TelemeterRealData_Series/alerts2w/01EPXBGA0413QZMTF4XQ0M4Q3E       4.05GB ± 0%    3.50GB ± 0%  -13.54%
TelemeterRealData_Series/alerts15s/01EPXBGA0413QZMTF4XQ0M4Q3E      1.09GB ± 0%    1.08GB ± 0%   -0.37%
TelemeterRealData_Series/subssyncs2w/01EPXBGA0413QZMTF4XQ0M4Q3E     663MB ± 0%     545MB ± 0%  -17.78%
TelemeterRealData_Series/subs2w/01EPXBGA0413QZMTF4XQ0M4Q3E         2.67GB ± 0%    2.22GB ± 0%  -16.99%
TelemeterRealData_Series/subs15s/01EPXBGA0413QZMTF4XQ0M4Q3E         631MB ± 0%     631MB ± 0%   +0.00%

name                                                             old allocs/op  new allocs/op  delta
TelemeterRealData_Series/alerts2w/01EPXBGA0413QZMTF4XQ0M4Q3E        38.7M ± 0%     15.5M ± 0%  -59.85%
TelemeterRealData_Series/alerts15s/01EPXBGA0413QZMTF4XQ0M4Q3E        412k ± 0%      229k ± 0%  -44.43%
TelemeterRealData_Series/subssyncs2w/01EPXBGA0413QZMTF4XQ0M4Q3E     5.85M ± 0%     2.10M ± 0%  -64.20%
TelemeterRealData_Series/subs2w/01EPXBGA0413QZMTF4XQ0M4Q3E          30.4M ± 0%      7.2M ± 0%  -76.31%
TelemeterRealData_Series/subs15s/01EPXBGA0413QZMTF4XQ0M4Q3E         38.4k ± 0%     38.5k ± 0%   +0.28%

Verification

[bwplotka]

Nice. I will check tomorrow but I still think we could just adjust symbolFactor to be something different than 32. If not 1.

This should also help with allocs, wonder what's the main source. I guess we could together Investigate profiles (:

[bwplotka]

Can you double check you are running this tests for more or equal than minute. Especially if something is taking long time, worth to rule out laptop resources saturation

[yeya24]

Can you double check you are running this tests for more or equal than minute. Especially if something is taking long time, worth to rule out laptop resources saturation

The result above is under 30s bench time. I did another round of benchmarks with 1m bench time and the result is similar.

name                                                             old time/op    new time/op    delta
TelemeterRealData_Series/alerts2w/01EPXBGA0413QZMTF4XQ0M4Q3E        14.7s ± 0%      8.3s ± 0%  -43.40%
TelemeterRealData_Series/alerts15s/01EPXBGA0413QZMTF4XQ0M4Q3E       3.50s ± 0%     3.32s ± 0%   -5.09%
TelemeterRealData_Series/subssyncs2w/01EPXBGA0413QZMTF4XQ0M4Q3E     2.55s ± 0%     1.14s ± 0%  -55.33%
TelemeterRealData_Series/subs2w/01EPXBGA0413QZMTF4XQ0M4Q3E          15.5s ± 0%      6.6s ± 0%  -57.26%
TelemeterRealData_Series/subs15s/01EPXBGA0413QZMTF4XQ0M4Q3E         2.22s ± 0%     2.02s ± 0%   -9.24%

name                                                             old alloc/op   new alloc/op   delta
TelemeterRealData_Series/alerts2w/01EPXBGA0413QZMTF4XQ0M4Q3E       4.05GB ± 0%    3.50GB ± 0%  -13.54%
TelemeterRealData_Series/alerts15s/01EPXBGA0413QZMTF4XQ0M4Q3E      1.09GB ± 0%    1.08GB ± 0%   -0.38%
TelemeterRealData_Series/subssyncs2w/01EPXBGA0413QZMTF4XQ0M4Q3E     663MB ± 0%     545MB ± 0%  -17.78%
TelemeterRealData_Series/subs2w/01EPXBGA0413QZMTF4XQ0M4Q3E         2.67GB ± 0%    2.22GB ± 0%  -16.99%
TelemeterRealData_Series/subs15s/01EPXBGA0413QZMTF4XQ0M4Q3E         631MB ± 0%     631MB ± 0%   -0.00%

name                                                             old allocs/op  new allocs/op  delta
TelemeterRealData_Series/alerts2w/01EPXBGA0413QZMTF4XQ0M4Q3E        38.7M ± 0%     15.5M ± 0%  -59.85%
TelemeterRealData_Series/alerts15s/01EPXBGA0413QZMTF4XQ0M4Q3E        412k ± 0%      229k ± 0%  -44.49%
TelemeterRealData_Series/subssyncs2w/01EPXBGA0413QZMTF4XQ0M4Q3E     5.85M ± 0%     2.10M ± 0%  -64.20%
TelemeterRealData_Series/subs2w/01EPXBGA0413QZMTF4XQ0M4Q3E          30.4M ± 0%      7.2M ± 0%  -76.31%
TelemeterRealData_Series/subs15s/01EPXBGA0413QZMTF4XQ0M4Q3E         38.5k ± 0%     38.4k ± 0%   -0.10%

Also tested with symbolFactor value 1 and 2, but seems using the default value 32 gives a better performance with the existing benchmark.

[bwplotka]

Awesome, thanks for checking, I want to try something additional before we move to this 🤗

[bwplotka]

I was thinking about something like this: #3561

Will compare the results from your PR as well (:

[bwplotka]

Interesting, looks like caching is better:

[bwplotka]

Let's go for this!

Since you are maintainer @yeya24 you should have write access to repo and CI now (: Can you restart flaky test? ;p

[csmarchbanks]

I just want to chime in and say it is awesome to see this optimization helping out other parts of Thanos too!

[yeya24]

CI passed. Let's try it!