how did kafka use page cache to speed up
<p>I'm curious how did kafka use linux page cache to speed up message?</p>

<p>say producer A send message mA, so kafka decide to append it to file fA, so kafka will call save API, then the mA goes from kafka memory to system buffer, then copied to page cache, or directly copied to page cache?</p>

<p>then one consumer B needs to read message mA, kafka calculated and decide the mA is in file fA, so it call read, in which linux copy the message from page cache to system buffer, then copied to kafka memory buffer, then kafka call network send, which copy the kafka memory buffer to system buffer, then send it to network card driver.</p>

<p>am I correct? but still a lot of extra copy.</p>