From fc775f2e313c08732632513e41a7eea7aae5048e Mon Sep 17 00:00:00 2001
From: Samuel Angebault <staphylo@arista.com>
Date: Fri, 24 Feb 2023 10:08:04 -0800
Subject: [PATCH] [Arista] Disable SSD NCQ on Lodoga (#13964)

Why I did it
Fix similar issue seen on #13739 but only for DCS-7050CX3-32S

How I did it
Add a kernel parameter to tell libata to disable NCQ

How to verify it
The message ata2.00: FORCE: horkage modified (noncq) should appear on the dmesg.

Test results using: fio --direct=1 --rw=randrw --bs=64k --ioengine=libaio --iodepth=64 --runtime=120 --numjobs=4

with NCQ

   READ: bw=26.1MiB/s (27.4MB/s), 26.1MiB/s-26.1MiB/s (27.4MB/s-27.4MB/s), io=3136MiB (3288MB), run=120053-120053msec
  WRITE: bw=26.3MiB/s (27.6MB/s), 26.3MiB/s-26.3MiB/s (27.6MB/s-27.6MB/s), io=3161MiB (3315MB), run=120053-120053msec
without NCQ

   READ: bw=22.0MiB/s (23.1MB/s), 22.0MiB/s-22.0MiB/s (23.1MB/s-23.1MB/s), io=2647MiB (2775MB), run=120069-120069msec
  WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=2665MiB (2795MB), run=120069-120069msec
---
 files/Aboot/boot0.j2 | 1 +
 1 file changed, 1 insertion(+)

diff --git a/files/Aboot/boot0.j2 b/files/Aboot/boot0.j2
index 70534a4a0c3f..f40fef8162f5 100644
--- a/files/Aboot/boot0.j2
+++ b/files/Aboot/boot0.j2
@@ -526,6 +526,7 @@ write_platform_specific_cmdline() {
     if [ "$sid" = "Lodoga" ]; then
         aboot_machine=arista_7050cx3_32s
         cmdline_add logs_inram=on
+        cmdline_add libata.force=2.00:noncq
     fi
     if [ "$sid" = "Marysville" ]; then
         aboot_machine=arista_7050sx3_48yc8