On Wed, 9 Jan 2019 at 18:26, Ladislav Michl <ladis@xxxxxxxxxxxxxx> wrote: > > On Wed, Jan 09, 2019 at 05:32:31PM +0100, Vincent Guittot wrote: > > On Wed, 9 Jan 2019 at 17:07, Ladislav Michl <ladis@xxxxxxxxxxxxxx> wrote: > > > > > > 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 <ladis@xxxxxxxxxxxxxx> 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: > > > > This one looks good for me > > Lets split is for 'comments fix' patch, which was just send and 'the rest'. > Now, 'the rest' can either be v2 of your "PM/runtime: Fix autosuspend_delay on > 32bits arch" or will wait for 5.1. You decide :) I don't really mind. Rafael, Do you prefer to only take the fix for u64 casting problem or do you prefer to also take the optimization below in one single patch ? > > > > 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 <pm_runtime_autosuspend_expiration>: > > > 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 <pm_runtime_autosuspend_expiration+0x44> > > > 490: e59030e4 ldr r3, [r0, #228] ; 0xe4 > > > 494: e3530000 cmp r3, #0 > > > 498: ba000009 blt 4c4 <pm_runtime_autosuspend_expiration+0x44> > > > 49c: e28050e8 add r5, r0, #232 ; 0xe8 > > > 4a0: e8950030 ldm r5, {r4, r5} > > > 4a4: e59f2030 ldr r2, [pc, #48] ; 4dc <pm_runtime_autosuspend_expiration+0x5c> > > > 4a8: e0e54392 smlal r4, r5, r2, r3 > > > 4ac: ebfffffe bl 0 <ktime_get> > > > 4b0: e1550001 cmp r5, r1 > > > 4b4: 01540000 cmpeq r4, r0 > > > 4b8: e1a06004 mov r6, r4 > > > 4bc: e1a07005 mov r7, r5 > > > 4c0: 8a000001 bhi 4cc <pm_runtime_autosuspend_expiration+0x4c> > > > 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 <pm_runtime_autosuspend_expiration.part.0>: > > > 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 <pm_runtime_autosuspend_expiration.part.0+0x29> > > > 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 <pm_runtime_autosuspend_expiration.part.0+0x24> > > > 254: 48 39 c3 cmp %rax,%rbx > > > 257: 77 02 ja 25b <pm_runtime_autosuspend_expiration.part.0+0x2b> > > > 259: 31 db xor %ebx,%ebx > > > 25b: 48 89 d8 mov %rbx,%rax > > > 25e: 5b pop %rbx > > > 25f: c3 retq > > > > > > 00000000000002a0 <pm_runtime_autosuspend_expiration>: > > > 2a0: f6 87 91 01 00 00 04 testb $0x4,0x191(%rdi) > > > 2a7: 74 02 je 2ab <pm_runtime_autosuspend_expiration+0xb> > > > 2a9: eb 85 jmp 230 <pm_runtime_autosuspend_expiration.part.0> > > > 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 <pm_runtime_autosuspend_expiration>: > > > 110: e92d41f0 push {r4, r5, r6, r7, r8, lr} > > > 114: e1a06000 mov r6, r0 > > > 118: ebfffffe bl 0 <ktime_get> > > > 11c: e5d630d1 ldrb r3, [r6, #209] ; 0xd1 > > > 120: e3130004 tst r3, #4 > > > 124: 0a00000d beq 160 <pm_runtime_autosuspend_expiration+0x50> > > > 128: e596c0e4 ldr ip, [r6, #228] ; 0xe4 > > > 12c: e35c0000 cmp ip, #0 > > > 130: ba00000a blt 160 <pm_runtime_autosuspend_expiration+0x50> > > > 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 <pm_runtime_autosuspend_expiration+0x68> > > > 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 <pm_runtime_autosuspend_expiration+0x58> > > > 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