From: Alex Ainscow Date: Thu, 5 Feb 2026 13:08:10 +0000 (+0000) Subject: docs: Update design document X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=a93bb95e51982d23a898cbc461e9f82ed004e6d3;p=ceph-ci.git docs: Update design document Signed-off-by: Alex Ainscow --- diff --git a/doc/dev/osd_internals/erasure_coding/direct_reads.rst b/doc/dev/osd_internals/erasure_coding/direct_reads.rst index 23337b24fa4..fcda38a8951 100644 --- a/doc/dev/osd_internals/erasure_coding/direct_reads.rst +++ b/doc/dev/osd_internals/erasure_coding/direct_reads.rst @@ -260,14 +260,16 @@ switched off: the bypass code must be trivially simple. Throttling Considerations ~~~~~~~~~~~~~~~~~~~~~~~~~ -This change presents a challenge for the existing throttling framework. It is -critical that the throttling behavior for a single logical client read remains -consistent, regardless of how many physical OSD operations it is split into. -The precise method for ensuring that the throttling scheduler correctly -accounts for these fragmented operations as a single logical unit is an open -problem that requires further investigation. As such, the design for this -component is not yet finalised and will be addressed during the implementation -phase. +The only place this code interacts with any "throttling" code is the Objecter +"throttle" mechanism. This is a simple mechanism which collects two metrics +which it calls "bytes" - derived from bytes transferred, and "ops". The SplitOp +mechanism will be inserted after the throttle processing has completed. No +attempt will be made to mark a direct reads as multiple ops. We can justify this +because: + +- Avoids changing client behaviour too much. +- If ops are being split into direct reads, the bytes metric should dominate. +- This is the simpler approach. Replica Balanced Reads ----------------------