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charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-OriginatorOrg: amperecomputing.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: BL1PR01MB7649.prod.exchangelabs.com X-MS-Exchange-CrossTenant-Network-Message-Id: fae45821-08a7-453a-8ef9-08de3da1ad27 X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Dec 2025 19:22:53.6027 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 3bc2b170-fd94-476d-b0ce-4229bdc904a7 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: Xa2K0duPfBPotO8nYq4Z/sl93NIkkvV8a031avoi4k+1zt/2ExjPKvbviWgk6opgLUZxtyH8ZwKIlMVwgF37LGPmfEZ4VynaubDs/4Nr6SA= X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR01MB994301 Hi Zhan, The cleanup looks nice, but these helpers are sitting in some very critical= hot paths. `update_stats_wait_end_fair` and `update_stats_enqueue_sleeper_= fair` are hit on practically every task wakeup and context switch.=20 Even though it's not a functional refactoring, have you verified it with an= y benchmarks? I'm concerned that introducing the helper and passing around = addresses of local variables (&stats, &p) might make it harder for the comp= iler to optimize compared to the original version. I'm actually looking at a similar improvement in the PELT area, so I'd be c= urious to know if you've seen any measurable change in overhead.. To help t= he compiler, it might be better to have the helper return the stats pointer= directly rather than passing &stats. This avoids the double indirection an= d makes it easier for the compiler to keep everything in registers. Also, g= iven how hot these paths are, using `__always_inline` would be safer than j= ust `inline` to reduce function call overhead. 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charset="us-ascii" Content-ID: <6FBC21151BDAA245BC5F65AA36C3B3CE@prod.exchangelabs.com> Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-OriginatorOrg: amperecomputing.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: BL1PR01MB7649.prod.exchangelabs.com X-MS-Exchange-CrossTenant-Network-Message-Id: b53be026-cb1d-468a-524e-08de3da1acd7 X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Dec 2025 19:22:52.8805 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 3bc2b170-fd94-476d-b0ce-4229bdc904a7 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 5R3rmSeKj/tW6irdzM0axMChqPZiX/AhZe91D6fbkFVpApRQu97jW34tV1HjxGRoKx0tglztsWMi14rGD1M8TBbgjvnuT+FXk04E0lOXZIk= X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR01MB994301 Message-ID: <20251217192252.f53d_umoncm4uBo6SFE3YK62O9O-eSVVVbdShS9gR2s@z> Hi Zhan, The cleanup looks nice, but these helpers are sitting in some very critical= hot paths. `update_stats_wait_end_fair` and `update_stats_enqueue_sleeper_= fair` are hit on practically every task wakeup and context switch.=20 Even though it's not a functional refactoring, have you verified it with an= y benchmarks? I'm concerned that introducing the helper and passing around = addresses of local variables (&stats, &p) might make it harder for the comp= iler to optimize compared to the original version. I'm actually looking at a similar improvement in the PELT area, so I'd be c= urious to know if you've seen any measurable change in overhead.. To help t= he compiler, it might be better to have the helper return the stats pointer= directly rather than passing &stats. This avoids the double indirection an= d makes it easier for the compiler to keep everything in registers. Also, g= iven how hot these paths are, using `__always_inline` would be safer than j= ust `inline` to reduce function call overhead. Thanks, Shubhang Kaushik=