From c146a0501df6843c23036c5bd3aaa683eda9f504 Mon Sep 17 00:00:00 2001 From: warner <> Date: Sun, 20 May 2012 18:03:59 +0000 Subject: [PATCH] doubts about MDMF download "linear in k" slowdown [Imported from Trac: page Performance/Sep2011, version 5] --- Performance/Sep2011.md | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/Performance/Sep2011.md b/Performance/Sep2011.md index bac69f5..e5acf62 100644 --- a/Performance/Sep2011.md +++ b/Performance/Sep2011.md @@ -94,3 +94,27 @@ Some graphs were added to Complete benchmark toolchain and data included in [atlasperf.git.tar.gz](../raw/attachments/Performance/Sep2011/atlasperf.git.tar.gz) + +Zooko raised the question (20-May-2012) on IRC: +``` + warner: this page says that K=60 takes twice as long as K=30: + https://tahoe-lafs.org/trac/tahoe-lafs/wiki/Performance/Sep2011 + But these graphs seems to show those two taking about the same time as +each other: + +https://tahoe-lafs.org/trac/tahoe-lafs/attachment/wiki/Performance/Sep2011/MDMF-100MB-partial.png + +https://tahoe-lafs.org/trac/tahoe-lafs/attachment/wiki/Performance/Sep2011/MDMF-1MB-partial.png + I hope the latter is true. :-) +``` + +Those partial-read graphs certainly don't show a linear difference +between k=30 and k=60. At best there might be a 4% difference between +k=3 and k=30, and k=30/k=60 look identical. + +I think I was prompted to write that sentence by looking at the yellow +"trunk-MDMF" line in the [CHKMDMF-100MB-vs-k.png](../raw/attachments/Performance/Sep2011/CHKMDMF-100MB-vs-k.png) graph, which +*does* show a linear slowdown with increasing k (with a lower multiplier +than the new-immutable-downloader). I don't know how to reconcile the +two. So something is funny, and I need to review the data, and possible +run new tests.