From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3539C43387 for ; Wed, 9 Jan 2019 16:07:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84A28206BB for ; Wed, 9 Jan 2019 16:07:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732549AbfAIQHk (ORCPT ); Wed, 9 Jan 2019 11:07:40 -0500 Received: from eddie.linux-mips.org ([148.251.95.138]:50410 "EHLO cvs.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731882AbfAIQHk (ORCPT ); Wed, 9 Jan 2019 11:07:40 -0500 Received: (from localhost user: 'ladis' uid#1021 fake: STDIN (ladis@eddie.linux-mips.org)) by eddie.linux-mips.org id S23993997AbfAIQHhQ3aSs (ORCPT + 2 others); Wed, 9 Jan 2019 17:07:37 +0100 Date: Wed, 9 Jan 2019 17:07:36 +0100 From: Ladislav Michl To: Vincent Guittot Cc: Tony Lindgren , "Rafael J. Wysocki" , Ulf Hansson , "open list:THERMAL" , linux-kernel , LAK , linux-omap@vger.kernel.org Subject: Re: Regression in v5.0-rc1 with autosuspend hrtimers Message-ID: <20190109160736.GA7416@lenoch> References: <20190108155354.GL5544@atomide.com> <20190108213743.GN5544@atomide.com> <20190109014218.GA8363@linaro.org> <20190109111703.GA28605@lenoch> <20190109115824.GA1353@lenoch> <20190109133337.GA13579@lenoch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 09, 2019 at 03:12:25PM +0100, Vincent Guittot wrote: > Please keep all thread list when replying :-) Ahh, sorry for that... [snip] > On Wed, 9 Jan 2019 at 14:33, Ladislav Michl wrote: > > I agree, but it doea all the magic correctly, so you won't need > > to touch that code is ktime_t changes (I know, unlikely..) > > But the current implementation doesn't care of any changes in ktime_t > as it uses raw ns Fair enough, so let's go back to: diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 70624695b6d5..e61ee9b47a26 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -121,7 +121,7 @@ static void pm_runtime_cancel_pending(struct device *dev) * Compute the autosuspend-delay expiration time based on the device's * power.last_busy time. If the delay has already expired or is disabled * (negative) or the power.use_autosuspend flag isn't set, return 0. - * Otherwise return the expiration time in jiffies (adjusted to be nonzero). + * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero). * * This function may be called either with or without dev->power.lock held. * Either way it can be racy, since power.last_busy may be updated at any time. @@ -129,24 +129,21 @@ static void pm_runtime_cancel_pending(struct device *dev) u64 pm_runtime_autosuspend_expiration(struct device *dev) { int autosuspend_delay; - u64 last_busy, expires = 0; - u64 now = ktime_to_ns(ktime_get()); + u64 expires; if (!dev->power.use_autosuspend) - goto out; + return 0; autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay); if (autosuspend_delay < 0) - goto out; - - last_busy = READ_ONCE(dev->power.last_busy); + return 0; - expires = last_busy + autosuspend_delay * NSEC_PER_MSEC; - if (expires <= now) - expires = 0; /* Already expired. */ + expires = READ_ONCE(dev->power.last_busy); + expires += NSEC_PER_MSEC * (u64)autosuspend_delay; + if (expires > ktime_to_ns(ktime_get())) + return expires; /* Expires in the future */ - out: - return expires; + return 0; } EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration); Which gives for arm: 00000480 : 480: e92d41f0 push {r4, r5, r6, r7, r8, lr} 484: e5d030d1 ldrb r3, [r0, #209] ; 0xd1 488: e3130004 tst r3, #4 48c: 0a00000c beq 4c4 490: e59030e4 ldr r3, [r0, #228] ; 0xe4 494: e3530000 cmp r3, #0 498: ba000009 blt 4c4 49c: e28050e8 add r5, r0, #232 ; 0xe8 4a0: e8950030 ldm r5, {r4, r5} 4a4: e59f2030 ldr r2, [pc, #48] ; 4dc 4a8: e0e54392 smlal r4, r5, r2, r3 4ac: ebfffffe bl 0 4b0: e1550001 cmp r5, r1 4b4: 01540000 cmpeq r4, r0 4b8: e1a06004 mov r6, r4 4bc: e1a07005 mov r7, r5 4c0: 8a000001 bhi 4cc 4c4: e3a06000 mov r6, #0 4c8: e3a07000 mov r7, #0 4cc: e1a00006 mov r0, r6 4d0: e1a01007 mov r1, r7 4d4: e8bd41f0 pop {r4, r5, r6, r7, r8, lr} 4d8: e12fff1e bx lr 4dc: 000f4240 .word 0x000f4240 And x86: 0000000000000230 : 230: 8b 87 a4 01 00 00 mov 0x1a4(%rdi),%eax 236: 53 push %rbx 237: 85 c0 test %eax,%eax 239: 78 1e js 259 23b: 48 63 d8 movslq %eax,%rbx 23e: 48 8b 97 a8 01 00 00 mov 0x1a8(%rdi),%rdx 245: 48 69 db 40 42 0f 00 imul $0xf4240,%rbx,%rbx 24c: 48 01 d3 add %rdx,%rbx 24f: e8 00 00 00 00 callq 254 254: 48 39 c3 cmp %rax,%rbx 257: 77 02 ja 25b 259: 31 db xor %ebx,%ebx 25b: 48 89 d8 mov %rbx,%rax 25e: 5b pop %rbx 25f: c3 retq 00000000000002a0 : 2a0: f6 87 91 01 00 00 04 testb $0x4,0x191(%rdi) 2a7: 74 02 je 2ab 2a9: eb 85 jmp 230 2ab: 31 c0 xor %eax,%eax 2ad: c3 retq 2ae: 66 90 xchg %ax,%ax [snip] > > Well, main concern was not to call ktime_get at the beginning of function > > as it is not too cheap. > > Doesn't the compiler optimize that to just before the test ? No (compare with above). And it is also almost certain that someone will run script and send "...do not needlesly initialize..." patch :) gcc version 8.2.1 20181130 (OSELAS.Toolchain-2018.12.0 8-20181130) 00000110 : 110: e92d41f0 push {r4, r5, r6, r7, r8, lr} 114: e1a06000 mov r6, r0 118: ebfffffe bl 0 11c: e5d630d1 ldrb r3, [r6, #209] ; 0xd1 120: e3130004 tst r3, #4 124: 0a00000d beq 160 128: e596c0e4 ldr ip, [r6, #228] ; 0xe4 12c: e35c0000 cmp ip, #0 130: ba00000a blt 160 134: e28630e8 add r3, r6, #232 ; 0xe8 138: e893000c ldm r3, {r2, r3} 13c: e1a05001 mov r5, r1 140: e1a04000 mov r4, r0 144: e59f002c ldr r0, [pc, #44] ; 178 148: e0010c90 mul r1, r0, ip 14c: e0926001 adds r6, r2, r1 150: e0a37fc1 adc r7, r3, r1, asr #31 154: e1550007 cmp r5, r7 158: 01540006 cmpeq r4, r6 15c: 3a000001 bcc 168 160: e3a06000 mov r6, #0 164: e3a07000 mov r7, #0 168: e1a00006 mov r0, r6 16c: e1a01007 mov r1, r7 170: e8bd41f0 pop {r4, r5, r6, r7, r8, lr} 174: e12fff1e bx lr 178: 000f4240 .word 0x000f4240 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E650DC43387 for ; Wed, 9 Jan 2019 16:07:44 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B5EDB214C6 for ; Wed, 9 Jan 2019 16:07:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="haBvw8rf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5EDB214C6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-mips.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=fw1Nd1Td8OxFtvwoLhQYcQzdnew0s4q+K5XhUo+r9ZM=; b=haBvw8rff2Qn/R 2KG0jLkRahescdc8t1ASGaNCNHYvPv+IaqpJsrfdy1KQgAR3dGfXog35bz3WYYXuaC2CL0i+dAqML R47YCYPjYVdjVAu3rrfmkjwd6W0/G/iWlzrYW5EyBSZr+ayQpwQm0vSxrVdPk8I/T6eDB7SYCaLoU DE2LJjDO1DQgN1TMQHxh7nA8hZQaAxNJQKy5kqhepan3dPXgaURCLEqrNXzW898SJlrskWozMHGUz pGHmVm1Fg12hlOks8U19VXmUqm91Hhc689fWxxTIimYwMpycSiOm3CAZkgiQCj6mUCxkjclNZf5vB u/GcCWons8N4UmiFy1Vg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ghGON-0002lu-62; Wed, 09 Jan 2019 16:07:43 +0000 Received: from eddie.linux-mips.org ([148.251.95.138] helo=cvs.linux-mips.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ghGOK-0002lW-0e for linux-arm-kernel@lists.infradead.org; Wed, 09 Jan 2019 16:07:41 +0000 Received: (from localhost user: 'ladis' uid#1021 fake: STDIN (ladis@eddie.linux-mips.org)) by eddie.linux-mips.org id S23993997AbfAIQHhQ3aSs (ORCPT ); Wed, 9 Jan 2019 17:07:37 +0100 Date: Wed, 9 Jan 2019 17:07:36 +0100 From: Ladislav Michl To: Vincent Guittot Subject: Re: Regression in v5.0-rc1 with autosuspend hrtimers Message-ID: <20190109160736.GA7416@lenoch> References: <20190108155354.GL5544@atomide.com> <20190108213743.GN5544@atomide.com> <20190109014218.GA8363@linaro.org> <20190109111703.GA28605@lenoch> <20190109115824.GA1353@lenoch> <20190109133337.GA13579@lenoch> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190109_080740_054261_DEAD1EA1 X-CRM114-Status: GOOD ( 16.49 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ulf Hansson , "open list:THERMAL" , Tony Lindgren , "Rafael J. Wysocki" , linux-kernel , linux-omap@vger.kernel.org, LAK Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jan 09, 2019 at 03:12:25PM +0100, Vincent Guittot wrote: > Please keep all thread list when replying :-) Ahh, sorry for that... [snip] > On Wed, 9 Jan 2019 at 14:33, Ladislav Michl wrote: > > I agree, but it doea all the magic correctly, so you won't need > > to touch that code is ktime_t changes (I know, unlikely..) > > But the current implementation doesn't care of any changes in ktime_t > as it uses raw ns Fair enough, so let's go back to: diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 70624695b6d5..e61ee9b47a26 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -121,7 +121,7 @@ static void pm_runtime_cancel_pending(struct device *dev) * Compute the autosuspend-delay expiration time based on the device's * power.last_busy time. If the delay has already expired or is disabled * (negative) or the power.use_autosuspend flag isn't set, return 0. - * Otherwise return the expiration time in jiffies (adjusted to be nonzero). + * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero). * * This function may be called either with or without dev->power.lock held. * Either way it can be racy, since power.last_busy may be updated at any time. @@ -129,24 +129,21 @@ static void pm_runtime_cancel_pending(struct device *dev) u64 pm_runtime_autosuspend_expiration(struct device *dev) { int autosuspend_delay; - u64 last_busy, expires = 0; - u64 now = ktime_to_ns(ktime_get()); + u64 expires; if (!dev->power.use_autosuspend) - goto out; + return 0; autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay); if (autosuspend_delay < 0) - goto out; - - last_busy = READ_ONCE(dev->power.last_busy); + return 0; - expires = last_busy + autosuspend_delay * NSEC_PER_MSEC; - if (expires <= now) - expires = 0; /* Already expired. */ + expires = READ_ONCE(dev->power.last_busy); + expires += NSEC_PER_MSEC * (u64)autosuspend_delay; + if (expires > ktime_to_ns(ktime_get())) + return expires; /* Expires in the future */ - out: - return expires; + return 0; } EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration); Which gives for arm: 00000480 : 480: e92d41f0 push {r4, r5, r6, r7, r8, lr} 484: e5d030d1 ldrb r3, [r0, #209] ; 0xd1 488: e3130004 tst r3, #4 48c: 0a00000c beq 4c4 490: e59030e4 ldr r3, [r0, #228] ; 0xe4 494: e3530000 cmp r3, #0 498: ba000009 blt 4c4 49c: e28050e8 add r5, r0, #232 ; 0xe8 4a0: e8950030 ldm r5, {r4, r5} 4a4: e59f2030 ldr r2, [pc, #48] ; 4dc 4a8: e0e54392 smlal r4, r5, r2, r3 4ac: ebfffffe bl 0 4b0: e1550001 cmp r5, r1 4b4: 01540000 cmpeq r4, r0 4b8: e1a06004 mov r6, r4 4bc: e1a07005 mov r7, r5 4c0: 8a000001 bhi 4cc 4c4: e3a06000 mov r6, #0 4c8: e3a07000 mov r7, #0 4cc: e1a00006 mov r0, r6 4d0: e1a01007 mov r1, r7 4d4: e8bd41f0 pop {r4, r5, r6, r7, r8, lr} 4d8: e12fff1e bx lr 4dc: 000f4240 .word 0x000f4240 And x86: 0000000000000230 : 230: 8b 87 a4 01 00 00 mov 0x1a4(%rdi),%eax 236: 53 push %rbx 237: 85 c0 test %eax,%eax 239: 78 1e js 259 23b: 48 63 d8 movslq %eax,%rbx 23e: 48 8b 97 a8 01 00 00 mov 0x1a8(%rdi),%rdx 245: 48 69 db 40 42 0f 00 imul $0xf4240,%rbx,%rbx 24c: 48 01 d3 add %rdx,%rbx 24f: e8 00 00 00 00 callq 254 254: 48 39 c3 cmp %rax,%rbx 257: 77 02 ja 25b 259: 31 db xor %ebx,%ebx 25b: 48 89 d8 mov %rbx,%rax 25e: 5b pop %rbx 25f: c3 retq 00000000000002a0 : 2a0: f6 87 91 01 00 00 04 testb $0x4,0x191(%rdi) 2a7: 74 02 je 2ab 2a9: eb 85 jmp 230 2ab: 31 c0 xor %eax,%eax 2ad: c3 retq 2ae: 66 90 xchg %ax,%ax [snip] > > Well, main concern was not to call ktime_get at the beginning of function > > as it is not too cheap. > > Doesn't the compiler optimize that to just before the test ? No (compare with above). And it is also almost certain that someone will run script and send "...do not needlesly initialize..." patch :) gcc version 8.2.1 20181130 (OSELAS.Toolchain-2018.12.0 8-20181130) 00000110 : 110: e92d41f0 push {r4, r5, r6, r7, r8, lr} 114: e1a06000 mov r6, r0 118: ebfffffe bl 0 11c: e5d630d1 ldrb r3, [r6, #209] ; 0xd1 120: e3130004 tst r3, #4 124: 0a00000d beq 160 128: e596c0e4 ldr ip, [r6, #228] ; 0xe4 12c: e35c0000 cmp ip, #0 130: ba00000a blt 160 134: e28630e8 add r3, r6, #232 ; 0xe8 138: e893000c ldm r3, {r2, r3} 13c: e1a05001 mov r5, r1 140: e1a04000 mov r4, r0 144: e59f002c ldr r0, [pc, #44] ; 178 148: e0010c90 mul r1, r0, ip 14c: e0926001 adds r6, r2, r1 150: e0a37fc1 adc r7, r3, r1, asr #31 154: e1550007 cmp r5, r7 158: 01540006 cmpeq r4, r6 15c: 3a000001 bcc 168 160: e3a06000 mov r6, #0 164: e3a07000 mov r7, #0 168: e1a00006 mov r0, r6 16c: e1a01007 mov r1, r7 170: e8bd41f0 pop {r4, r5, r6, r7, r8, lr} 174: e12fff1e bx lr 178: 000f4240 .word 0x000f4240 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel