Karmayoga is a much abused concept these days,nowadays people think that it is doing whatever job one’s bosses or political superiors assign to them perfectly and chores)pleasingly(or even daily. Or sometimes school students are told that their studying hard and getting good grades means they are good karmayogis, but no,it means nothing like that. This idea had its origins amongst(specifically) shuklayajurvaidika circles(as noted in the 2nd mantra of the ishopanishad). Karmayoga means doing one’s nitya and naimittika karmas and yAgas as laid down in the smArta systems as appropriate to one’s varNa while dedicating all its puNyas and other results to the supreme deity of whatever system your ideal is:vAsudeva,shiva,etc. In fact,this was probably the ideology of an old set of ritualists who later became the one of the groups that went into the formation of pA~NcharAtra:The mantrasiddhAntins are a group of brAhmaNas belonging to the kANva and mAdhyadina shAkhAs of the shuklayajurveda,who are supposed to meditate on vAsudeva as they are doing somayAga and dedicate their fruits to him. It is this strain of ritualist thought that found its expression in the karmayoga idea of the Gita(which,textually speaking is belonging to an old sAtavata esque strain of thought in ancient India). And of course,the other tendency of ancient Hindu thought to homologize all actions as ritual:even sex,would mean ending up in an Aurobindo-esque ‘All life is yoga.’ conclusion.
Above are verses from the charyapAda of the pAdmasaMhitA which note that the followers of mantrasiddhAnta do contemplation of vAsudeva with trayimantras(vedamantras),associated with the kANva and mAdhyadina shAkhAs,and thee brAhmaNas worship vAsudeva while performing somayAga. This was the original ideal of karmayoga,historically speaking.
An end (semi) rant: The vyAdha gItA has been completely hopelessly ripped out of its original context to a society which is scarcely little like anything that would have supported the historical-cum-mythical vyAdha.