[action] [PR:562] [cmis] add read only cache decorator#577
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mssonicbld merged 1 commit intosonic-net:202505from Jun 18, 2025
Merged
[action] [PR:562] [cmis] add read only cache decorator#577mssonicbld merged 1 commit intosonic-net:202505from
mssonicbld merged 1 commit intosonic-net:202505from
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Improve CMIS startup performance by adding a read-only cache decorator. #### Description This patch introduces read only cache decorator, which caches the results of static EEPROM-read methods in CmisApi to avoid redundant I2C transactions. By memoizing these methods, we greatly reduce the number of EEPROM reads during startup. Unit tests have been added to verify correct caching behavior and cache invalidation. Some problematic cable scenarios: If user could have issued reset since some fields in EEPROM were not accessible initially (the cable has some problem in this case, first plugin data read is incorrect, after re-plugin, then data will be correct.) In this case, with cache enabled, there is a WA: we can reset the sfp by xcvrd restart, then data will be correct. #### Motivation and Context On systems managing up to 512 CMIS ports, the cumulative cost of repeated EEPROM reads at startup causes noticeable delays. Caching static getter methods eliminates unnecessary I2C calls and speeds up initialization. #### How Has This Been Tested? Test with config reload, speed up around 2 seconds. Before: ```bash $ time sudo config reload -y Acquired lock on /etc/sonic/reload.lock Disabling container and routeCheck monitoring ... Stopping SONiC target ... Running command: /usr/local/bin/sonic-cfggen -j /etc/sonic/init_cfg.json -j /etc/sonic/config_db.json --write-to-db Running command: /usr/local/bin/db_migrator.py -o migrate Running command: /usr/local/bin/sonic-cfggen -d -y /etc/sonic/sonic_version.yml -t /usr/share/sonic/templates/sonic-environment.j2,/etc/sonic/sonic-environment Restarting SONiC target ... Enabling container and routeCheck monitoring ... Reloading Monit configuration ... Reinitializing monit daemon Released lock on /etc/sonic/reload.lock real 0m22.324s user 0m1.388s sys 0m0.361s ``` After: ```bash $ time sudo config reload -y -f Acquired lock on /etc/sonic/reload.lock Disabling container and routeCheck monitoring ... Stopping SONiC target ... Running command: /usr/local/bin/sonic-cfggen -j /etc/sonic/init_cfg.json -j /etc/sonic/config_db.json --write-to-db Running command: /usr/local/bin/db_migrator.py -o migrate Running command: /usr/local/bin/sonic-cfggen -d -y /etc/sonic/sonic_version.yml -t /usr/share/sonic/templates/sonic-environment.j2,/etc/sonic/sonic-environment Restarting SONiC target ... Enabling container and routeCheck monitoring ... Reloading Monit configuration ... Reinitializing monit daemon Released lock on /etc/sonic/reload.lock real 0m20.811s user 0m1.367s sys 0m0.361s ```
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Original PR: #562 |
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Improve CMIS startup performance by adding a read-only cache decorator.
Description
This patch introduces read only cache decorator, which caches the results of static EEPROM-read methods in CmisApi to avoid redundant I2C transactions. By memoizing these methods, we greatly reduce the number of EEPROM reads during startup. Unit tests have been added to verify correct caching behavior and cache invalidation.
Some problematic cable scenarios:
If user could have issued reset since some fields in EEPROM were not accessible initially (the cable has some problem in this case, first plugin data read is incorrect, after re-plugin, then data will be correct.) In this case, with cache enabled, there is a WA: we can reset the sfp by xcvrd restart, then data will be correct.
Motivation and Context
On systems managing up to 512 CMIS ports, the cumulative cost of repeated EEPROM reads at startup causes noticeable delays. Caching static getter methods eliminates unnecessary I2C calls and speeds up initialization.
How Has This Been Tested?
Test with config reload, speed up around 2 seconds.
Before:
$ time sudo config reload -y Acquired lock on /etc/sonic/reload.lock Disabling container and routeCheck monitoring ... Stopping SONiC target ... Running command: /usr/local/bin/sonic-cfggen -j /etc/sonic/init_cfg.json -j /etc/sonic/config_db.json --write-to-db Running command: /usr/local/bin/db_migrator.py -o migrate Running command: /usr/local/bin/sonic-cfggen -d -y /etc/sonic/sonic_version.yml -t /usr/share/sonic/templates/sonic-environment.j2,/etc/sonic/sonic-environment Restarting SONiC target ... Enabling container and routeCheck monitoring ... Reloading Monit configuration ... Reinitializing monit daemon Released lock on /etc/sonic/reload.lock real 0m22.324s user 0m1.388s sys 0m0.361sAfter:
$ time sudo config reload -y -f Acquired lock on /etc/sonic/reload.lock Disabling container and routeCheck monitoring ... Stopping SONiC target ... Running command: /usr/local/bin/sonic-cfggen -j /etc/sonic/init_cfg.json -j /etc/sonic/config_db.json --write-to-db Running command: /usr/local/bin/db_migrator.py -o migrate Running command: /usr/local/bin/sonic-cfggen -d -y /etc/sonic/sonic_version.yml -t /usr/share/sonic/templates/sonic-environment.j2,/etc/sonic/sonic-environment Restarting SONiC target ... Enabling container and routeCheck monitoring ... Reloading Monit configuration ... Reinitializing monit daemon Released lock on /etc/sonic/reload.lock real 0m20.811s user 0m1.367s sys 0m0.361s