public inbox for passt-dev@passt.top
 help / color / mirror / code / Atom feed
* [PATCH] test/README: Requirements for socket buffer sizes and hardware performance events
@ 2022-08-30 20:00 Stefano Brivio
  2022-09-01  1:37 ` David Gibson
  0 siblings, 1 reply; 2+ messages in thread
From: Stefano Brivio @ 2022-08-30 20:00 UTC (permalink / raw)
  To: passt-dev

[-- Attachment #1: Type: text/plain, Size: 1599 bytes --]

Performance tests use iperf3(1) with large windows, and these sysctl
entries are needed to run them unmodified.

The passt demo uses perf(1) to report syscall overhead, and that
needs access to hardware performance counters for unprivileged
users.

Reported-by: David Gibson <david(a)gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
---
 test/README.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/test/README.md b/test/README.md
index 581949a..72a4986 100644
--- a/test/README.md
+++ b/test/README.md
@@ -47,6 +47,22 @@ Virtual machine images are built during test executions using
 [mbuto](https://mbuto.lameexcu.se/), the shell script is sourced via _git_
 as needed, so there's no need to actually install it.
 
+### Kernel parameters
+
+Performance tests use iperf3 with rather large TCP receiving and sending
+windows, to decrease the likelihood of iperf3 itself becoming the bottleneck.
+These values need to be allowed by the kernel of the host running the tests.
+Example for /etc/sysctl.conf:
+
+  net.core.rmem_max = 134217728
+  net.core.wmem_max = 134217728
+
+Further, the passt demo uses perf(1), relying on hardware events for performance
+counters, to display syscall overhead. The kernel needs to allow unprivileged
+users to access these events. Suggested entry for /etc/sysctl.conf:
+
+  kernel.perf_event_paranoid = -1
+
 ### Special requirements for continuous integration and demo modes
 
 Running the test suite as continuous integration or demo modes will record the
-- 
@@ -47,6 +47,22 @@ Virtual machine images are built during test executions using
 [mbuto](https://mbuto.lameexcu.se/), the shell script is sourced via _git_
 as needed, so there's no need to actually install it.
 
+### Kernel parameters
+
+Performance tests use iperf3 with rather large TCP receiving and sending
+windows, to decrease the likelihood of iperf3 itself becoming the bottleneck.
+These values need to be allowed by the kernel of the host running the tests.
+Example for /etc/sysctl.conf:
+
+  net.core.rmem_max = 134217728
+  net.core.wmem_max = 134217728
+
+Further, the passt demo uses perf(1), relying on hardware events for performance
+counters, to display syscall overhead. The kernel needs to allow unprivileged
+users to access these events. Suggested entry for /etc/sysctl.conf:
+
+  kernel.perf_event_paranoid = -1
+
 ### Special requirements for continuous integration and demo modes
 
 Running the test suite as continuous integration or demo modes will record the
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2022-09-01  1:37 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-08-30 20:00 [PATCH] test/README: Requirements for socket buffer sizes and hardware performance events Stefano Brivio
2022-09-01  1:37 ` David Gibson

Code repositories for project(s) associated with this public inbox

	https://passt.top/passt

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for IMAP folder(s).