IRC.

1 files changed, 37 insertions, 0 deletions

diff --git a/open_issues/performance/ipc_virtual_copy.mdwn b/open_issues/performance/ipc_virtual_copy.mdwn
index 00fa7180..9708ab96 100644
--- a/open_issues/performance/ipc_virtual_copy.mdwn
+++ b/open_issues/performance/ipc_virtual_copy.mdwn
@@ -356,3 +356,40 @@ IRC, freenode, #hurd, 2011-09-06:
     <youpi> in PV it does not make sense: the guest already provides the
       translated page table
     <youpi> which is just faster than anything else
+
+IRC, freenode, #hurd, 2011-09-09:
+
+    <antrik> oh BTW, for another data point: dd zero->null gets around 225 MB/s
+      on my lowly 1 GHz Pentium3, with a blocksize of 32k
+    <antrik> (but only half of that with 256k blocksize, and even less with 1M)
+    <antrik> the system has been up for a while... don't know whether it's
+      faster on a freshly booted one
+
+IRC, freenode, #hurd, 2011-09-15:
+
+    <sudoman>
+      http://www.reddit.com/r/gnu/comments/k68mb/how_intelamd_inadvertently_fixed_gnu_hurd/
+    <sudoman> so is the dd command pointed to by that article a measure of io
+      performance?
+    <antrik> sudoman: no, not really
+    <antrik> it's basically the baseline of what is possible -- but the actual
+      slowness we experience is more due to very unoptimal disk access patterns
+    <antrik> though using KVM with writeback caching does actually help with
+      that...
+    <antrik> also note that the title of this post really makes no
+      sense... nested page tables should provide similar improvements for *any*
+      guest system doing VM manipulation -- it's not Hurd-specific at all
+    <sudoman> ok, that makes sense. thanks :)
+
+IRC, freenode, #hurd, 2011-09-16:
+
+    <slpz> antrik: I wrote that article (the one about How AMD/Intel fixed...)
+    <slpz> antrik: It's obviously a bit of an exaggeration, but it's true that
+      nested pages supposes a great improvement in the performance of Hurd
+      running on virtual machines
+    <slpz> antrik: and it's Hurd specific, as this system is more affected by
+      the cost of page faults
+    <slpz> antrik: and as the impact of virtualization on the performance is
+      much higher than (almost) any other OS.
+    <slpz> antrik: also, dd from /dev/zero to /dev/null it's a measure on how
+      fast OOL IPC is.