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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Jun 2024 04:35:54.3404 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 62c378d6-3196-4602-553a-08dc8e86f99f X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS1PEPF0001709C.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR12MB8249 X-Mailman-Approved-At: Tue, 18 Jun 2024 09:37:51 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Rich Felker , Andreas Larsson , Peter Zijlstra , Dave Hansen , x86@kernel.org, "James E.J. Bottomley" , linux-openrisc@vger.kernel.org, Guo Ren , linux-csky@vger.kernel.org, David Vernet , "H. Peter Anvin" , sparclinux@vger.kernel.org, Thomas Gleixner , Kees Cook , Jonas Bonn , Valentin Schneider , Vincent Guittot , Yoshinori Sato , linux-sh@vger.kernel.org, Helge Deller , "Rafael J. Wysocki" , Christophe Leroy , Tony Battersby , Ingo Molnar , Mel Gorman , "Naveen N. Rao" , Matt Turner , Benjamin Gray , Andrew Donnellan , "Paul E. McKenney" , Rik van Riel , Brian Gerst , Frederic Weisbecker , Xin Li , Richard Henderson , linuxppc-dev@lists.ozlabs.org, Nicholas Piggin , Stefan Kristiansson , Ivan Kokshaysky , Steven Rostedt , John Paul Adrian Glaubitz , Bjorn Helgaas , Stafford Horne , Dietmar Eggemann , linux-arm-kernel@lists.infradead.org, Ben Segall , Michal Simek , Daniel Lezcano , linux-parisc@vger.kernel.org, Tim Chen , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Julia Lawall , Dinh Nguyen , Leonardo Bras , "Gautham R. Shenoy" , linux-alpha@vger.kernel.org, Imran Khan , Borislav Petkov , Rick Edgecombe , Daniel Bristot de Oliveira , "David S. Miller" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hello Russell, On 6/15/2024 7:56 PM, Russell King (Oracle) wrote: > On Thu, Jun 13, 2024 at 06:15:59PM +0000, K Prateek Nayak wrote: >> o Dropping the ARM results since I never got my hands on the ARM64 >> system I used in my last testing. If I do manage to get my hands on it >> again, I'll rerun the experiments and share the results on the thread. >> To test the case where TIF_NOTIFY_IPI is not enabled for a particular >> architecture, I applied the series only until Patch 3 and tested the >> same on my x86 machine with a WARN_ON_ONCE() in do_idle() to check if >> tif_notify_ipi() ever return true and then repeated the same with >> Patch 4 applied. > > Confused. ARM (32-bit) or ARM64? You patch 32-bit ARM, but you don't > touch 64-bit Arm. "ARM" on its own in the context above to me suggests > 32-bit, since you refer to ARM64 later. > In my first RFC posting, I had shared the results for ipistorm on an ARM64 server [1]. Vincent and Linus Walleij brought to my attention that ARM32 and ARM64 do not share the thread info flags and I probably saw a one-off behavior during my testing. Since then, it has been slightly challenging to get my hands on that machine again in a stable condition to see if there was any scenario that I might have missed but I tried a bunch of things on my x86 machine to confirm that an arch that does not define the TIF_NOTIFY_IPI would not hit these changes. Rest assured, Patch 5 is for ARM32 machines that currently define TIF_POLLING_NRFLAG [1] https://lore.kernel.org/lkml/20240220171457.703-6-kprateek.nayak@amd.com/ -- Thanks and Regards, Prateek