Date: Thu, 17 May 2018 11:06:42 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: Johannes Lundberg <johalun0@gmail.com> Cc: freebsd-current <freebsd-current@freebsd.org> Subject: Re: Lag after resume culprit found Message-ID: <4d69b9f6-9406-74ba-1780-ac783adcf107@FreeBSD.org> In-Reply-To: <CAECmPwuKoQaD0M-wJagns_YCDMLy_qMnuy%2BceLF5UZtfE_1ehg@mail.gmail.com> References: <CAECmPwtULDe9GGK0PhnUa7_n=zxripJj9nh5m0RTF9XqKhXKYQ@mail.gmail.com> <acaa419d-891e-96b1-7c1f-3203857c07ec@FreeBSD.org> <CAECmPwsgQhMM6zu=EfV=DQ4VHzEMuQUjD%2B45O-TP=A2U9mM8Qg@mail.gmail.com> <CAECmPwuKoQaD0M-wJagns_YCDMLy_qMnuy%2BceLF5UZtfE_1ehg@mail.gmail.com>
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On 17/05/2018 10:56, Johannes Lundberg wrote: > > > On Thu, May 17, 2018 at 8:46 AM, Johannes Lundberg <johalun0@gmail.com > <mailto:johalun0@gmail.com>> wrote: > > > > On Thu, May 17, 2018 at 7:43 AM, Andriy Gapon <avg@freebsd.org > <mailto:avg@freebsd.org>> wrote: > > On 17/05/2018 02:07, Johannes Lundberg wrote: > > https://github.com/freebsd/freebsd/commit/66f063557f257baa9c8aeab9f933171eaa6e1cfa > <https://github.com/freebsd/freebsd/commit/66f063557f257baa9c8aeab9f933171eaa6e1cfa>; > > x86 cpususpend_handler: call wbinvd after setting suspend state bits > > That's very interesting and surprising. > That commit changes something that happens before suspend, it should not > have > any effect on the system state after resume. > > Does anyone have a theory of what could be wrong? > > > Nope but moving > CPU_CLR_ATOMIC(cpu, &suspended_cpus); > back to the end of that scope fixes it. > > > > I did some further testing. > Calling > CPU_CLR_ATOMIC(cpu, &suspended_cpus); > before > pmap_init_pat(); > is what "breaks" resume. > > Is this Intel only or this it happen on AMD as well (which this patch was > intended for)? Not sure about the PAT part, but fpuresume/npxresume would affect all platforms. It's a bit puzzling that doing PAT manipulations on one AP while another AP is being brought up is problematic. Probably there is something that I am missing. Thank you very much again for zeroing in on it. > > How to test (i915kms) > > > > Start X with glxgears > > Confirm running stable at 60 fps > > suspend/resume (S3) > > glxgears is now fluctuating between 10-40 fps. -- Andriy Gapon
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