On Thu, Sep 04, 2014 at 01:33:10PM +0200, Paolo Bonzini wrote: >Il 04/09/2014 11:53, Paolo Bonzini ha scritto: >> Il 03/09/2014 20:25, Chris J Arges ha scritto: >>> <snip> >>>> I'm not sure about the reason for the warp, but indeed the offset and >>>> uptime match (I'll check them against the trace tomorrow) so it's "just" >>>> that the VM's TSC base is not taken into account correctly. >>>> >>>> Can you gather another trace with the problematic patch reverted? >>>> >>>> Paolo >>>> >>> >>> Here is the third trace running with 0d3da0d2 reverted from the latest >>> kvm queue branch 11cc9ea3: >>> >>> http://people.canonical.com/~arges/kvm/trace-3.dat.xz >> >> Thanks! And---yay!---I reproduced it on another machine. > >And my bisection landed on the merge of the timer branch (commit >e7fda6c4c3c1a7d6996dd75fd84670fa0b5d448f). Here is the log: > >$ git bisect bad origin/master >$ git bisect good v3.16 >$ git bisect good kvm-3.17-1 # 42cbc04fd3b5e3f9b011bf9fa3ce0b3d1e10b58b > >good [ 6929.863545] loaded kvm module (v3.17-rc1-158-g451fd72219dd) >bad [ 6971.932790] loaded kvm module (for-linus) >bad [ 7216.073128] loaded kvm module (v3.16-6426-gae045e245542) >good [ 7286.198948] loaded kvm module (v3.16-3283-g53ee983378ff) >good [ 7350.534060] loaded kvm module (v3.16-rc7-1668-gaef4f5b6db65) >good [ 7439.037038] loaded kvm module (v3.16-4006-g91c2ff7708d4) >good [ 7481.188637] loaded kvm module (v3.16-rc6-450-g7ba3c21c17d0) >bad [ 7535.292730] loaded kvm module (v3.16-4635-ge7fda6c4c3c1) >good [ 7589.722691] loaded kvm module (v3.16-rc5-110-g9b0fd802e8c0) >good [ 7630.286418] loaded kvm module (v3.16-4467-ged5c41d30ef2) >good [ 7712.470986] loaded kvm module (v3.16-rc1-35-g885d078bfe92) >good [ 7763.443626] loaded kvm module (v3.16-rc1-381-g1b0733837a9b) >good [ 7825.497414] loaded kvm module (v3.16-rc5-116-g7806f60e1d20) >good [ 7893.174056] loaded kvm module (v3.16-rc1-384-gc6f1224573c3) > >This means that: > >- Tomasz's patch (commit 0d3da0d26e3c3515997c99451ce3b0ad1a69a36c) is >fine, it just enables the (wrong) master clock more often > >- the failure is within that branch. > >I then cherry-picked Tomasz's patch during a new bisection, and landed >on one of my original suspects: > >commit cbcf2dd3b3d4d990610259e8d878fc8dc1f17d80 >Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >Date: Wed Jul 16 21:04:54 2014 +0000 > > x86: kvm: Make kvm_get_time_and_clockread() nanoseconds based > > Convert the relevant base data right away to nanoseconds instead of > doing the conversion on every readout. Reduces text size by 160 > bytes. > > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Gleb Natapov <gleb@xxxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx > Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> > Yes, I also look into this bad commit recently which lead to guest hang after live migration or after local save/restore. Regards, Wanpeng Li >Again, here is the log: > >$ git bisect bad 953dec21aed4038464fec02f96a2f1b8701a5bce >$ git bisect good 1af447bd8cbfb808a320885d214555fb2d32e6e6 > >good [ 8384.334892] loaded kvm module (v3.16-rc5-81-g68f6783d2831) >bad [ 8525.975170] loaded kvm module (v3.16-rc5-99-gf519b1a2e08c) >good [ 8562.204988] loaded kvm module (v3.16-rc5-90-g41fa4215f8e8) >bad [ 8629.133287] loaded kvm module (v3.16-rc5-94-g48f18fd6addc) >bad [ 8772.846612] loaded kvm module (v3.16-rc5-92-gcbcf2dd3b3d4) >good [ 8836.509602] loaded kvm module (v3.16-rc5-91-gbb0b58127c5a) > >Paolo >-- >To unsubscribe from this list: send the line "unsubscribe kvm" in >the body of a message to majordomo@xxxxxxxxxxxxxxx >More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
