[llvm-dev] GSoC Proposal : Path Profiling Support
Xinliang David Li via llvm-dev
llvm-dev at lists.llvm.org
Tue Mar 22 16:23:28 PDT 2016
Hi Snehasish, thanks for writing up the proposal.
As it stands today, path profiling still has serious scalability issue that
prevents it from being usable by any optimization passes that may benefit
from it. On the other hand, sampling based approach can still be promising.
For instance, LBR can potentially together with static CFG constructed
from the binary can be used to form path(let) samples, which is the area
our intern will explore this summer. It will be interesting to see how the
sampling based approach matches up instrumentation based method in
detecting hot paths.
Independent of the method used in generating path profile data, your
proposed work on the path profile info representation and query APIs can be
shared.
thanks,
David
On Mon, Mar 21, 2016 at 3:07 PM, Snehasish Kumar <ska124 at sfu.ca> wrote:
> Hi
>
> I am pinging to find out if there is any interest to mentor this
> proposal for GSoC this year? I've submitted a draft via the GSoC
> website.
>
> David, Vedant it would be great if I could get some advice on refining
> the goals and particulars of the implementation.
> The version we use internally is not performance oriented and will
> require refactoring.
> Here is a link to the draft document [1].
>
> Thanks,
> Snehasish
>
>
> [1]
> https://docs.google.com/document/d/18i9FvD7FSqX6tNEXb83gzc0EC_STeS3bWOVf167sFWk/edit?usp=sharing
>
>
> On Wed, Mar 16, 2016 at 2:03 PM, Snehasish Kumar <ska124 at sfu.ca> wrote:
> > Hi David,
> >
> >> Are the data below all collected when only one function is picked for
> >> instrumentation?
> >
> > Yes, here is a list of the benchmarks and selected functions.
> >
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | blks | _Z19BlkSchlsEqEuroNoDivfffffif
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | bodytrack |
> >
> _ZN17ImageMeasurements11InsideErrorERK17ProjectedCylinderRK11BinaryImageRiS6_
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | bzip2 | BZ2_compressBlock
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | ferret | image_segment
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | fluidanimate | _Z13ComputeForcesv
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | freqmine |
> > _Z32FPArray_conditional_pattern_baseIhEiP7FP_treeiiT_
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | gcc | bitmap_operation
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | hmmer | P7Viterbi
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | lbm | LBM_performStreamCollide
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | mcf | price_out_impl
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | mcf2000 | price_out_impl
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | namd |
> > _ZN20ComputeNonbondedUtil26calc_pair_energy_fullelectEP9nonbonded
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | povray |
> >
> _ZN3povL24All_Sphere_IntersectionsEPNS_13Object_StructEPNS_10Ray_StructEPNS_13istack_structE
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | sjeng | gen
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | soplex | _ZN6soplex9CLUFactor16vSolveUrightNoNZEPdS1_Piid
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | sphinx | vector_gautbl_eval_logs3
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | streamcluster | _Z5pgainlP6PointsdPliP17pthread_barrier_t
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | swaptions | _Z21HJM_Swaption_BlockingPddddddiidS_PS_llii
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> > | h264ref | dct_luma_16x16
> > |
> >
> +-----------------+----------------------------------------------------------------------------------------------+
> >
> >> Do you have data when such manual selection is not done?
> >
> > At the moment, I do not.
> >
> >>
> >> thanks,
> >>
> >> David
> >>
> >>
> >>>
> >>> numpaths = Number of possible paths
> >>> epp+compile = Time taken to compute encoding, insert instrumentation
> and
> >>> compile to executable
> >>> compile = Time taken to compile to executable
> >>> execpaths = Number of paths dynamically executed
> >>> epp-exec-time = Execution time with instrumentation
> >>> exec-time = Normal execution time
> >>> epp-bin-size = Size of instrumented binary in bytes
> >>> bin-size = Size of binary
> >>> ** size of shared library in bytes = 598042
> >>>
> >>>
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | benchmark | numpaths | epp+compile | compile | execpaths |
> >>> epp-exec-time | exec-time | epp-bin-size | bin-size |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | blks | 2 | 0m1.036s | 0m1.008s | 2 |
> >>> 0m3.643s | 0m3.205s | 155931 | 155459 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | bodytrack | 29 | 0m4.907s | 0m4.881s | 5 |
> >>> 0m14.786s | 0m1.943s | 2125256 | 2124224 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | bzip2 | 60 | 0m1.274s | 0m1.268s | 3 |
> >>> 0m9.441s | 0m9.624s | 259125 | 258477 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | ferret | 360921 | 0m26.208s | 0m26.102s | 40 |
> >>> 0m10.342s | 0m6.224s | 8342571 | 8338588 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | fluidanimate | 384117 | 0m0.895s | 0m0.869s | 88 |
> >>> 0m56.631s | 0m1.294s | 202702 | 197878 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | freqmine | 45 | 0m1.220s | 0m1.214s | 18 |
> >>> 0m22.150s | 0m5.515s | 278615 | 277656 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | gcc | 6026 | 0m31.941s | 0m31.327s | 125 |
> >>> 1m30.139s | 0m36.601s | 6991413 | 6991245 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | hmmer | 1882 | 0m3.193s | 0m3.232s | 65 |
> >>> 0m58.911s | 0m2.474s | 744510 | 742806 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | mcf | 230 | 0m0.838s | 0m0.830s | 10 |
> >>> 0m11.097s | 0m3.074s | 162680 | 161736 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | mcf2000 | 1155 | 0m0.859s | 0m0.853s | 26 |
> >>> 0m24.169s | 0m4.625s | 166092 | 165213 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | povray | 17 | 0m8.543s | 0m8.552s | 4 |
> >>> 9m24.562s | 5m39.295s | 2388152 | 2387960 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | sjeng | 158740 | 0m1.648s | 0m1.637s | 280 |
> >>> 0m20.786s | 0m5.229s | 368841 | 368009 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | soplex | 30 | 0m4.849s | 0m4.848s | 24 |
> >>> 7m28.151s | 4m10.813s | 1244775 | 1242063 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | sphinx | 26 | 0m2.212s | 0m2.198s | 5 |
> >>> 1m36.291s | 0m13.811s | 543534 | 543358 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | streamcluster | 21121728 | 0m0.947s | 0m0.908s | 33 |
> >>> 0m50.212s | 0m5.986s | 191981 | 185438 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | swaptions | 20655 | 0m0.965s | 0m0.950s | 13 |
> >>> 0m0.263s | 0m0.178s | 193841 | 184274 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | h264ref | 24130 | 0m4.278s | 0m4.272s | 76 |
> >>> 3m26.701s | 3m4.461s | 816660 | 812396 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | lbm | 8 | 0m0.824s | 0m0.815s | 5 |
> >>> 6m29.685s | 1m39.180s | 150871 | 150327 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>> | namd | 59598954 | 0m4.124s | 0m4.139s | 43 |
> >>> 18m36.447s | 6m50.288s | 925863 | 925271 |
> >>>
> >>>
> +---------------+----------+-------------+-----------+-----------+---------------+-----------+--------------+----------+
> >>>
> >>>
> >>>
> >>> > > Open Issues :
> >>> > > + Update PathProfileInfo on CFG transformations ?
> >>>
> >>> > Could you clarify what this means?
> >>>
> >>> Changing the control flow graph of a routine may invalidate collected
> path
> >>> profiles. For example, splitting a block with an unconditional branch
> does
> >>> not change the profile, but introducing a conditional branch
> invalidates the
> >>> profile. The issue I would like to address is which transformations
> should
> >>> we allow as safe transformations and how should we update the internal
> path
> >>> profile data structures if we allow this at all.
> >>>
> >>> > > + Verify with PGOEdge info ?
> >>>
> >>> > Ditto.
> >>>
> >>> Verification with PGOEdge info implies that the edge frequencies
> derived
> >>> from path profiles and via instrprof should be equal.
> >>>
> >>> > > + Handle setjmp, longjmp, early program termination, noreturn calls
> >>>
> >>> > How do you handle indirect calls?
> >>>
> >>> No special handling of indirect calls as path profiles are
> >>> intra-procedural and control returns to same basic block
> >>> after call in the general case. For the above mentioned cases, control
> may
> >>> not return.
> >>>
> >>>
> >>> Regards,
> >>> Snehasish
> >>> _______________________________________________
> >>> LLVM Developers mailing list
> >>> llvm-dev at lists.llvm.org
> >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>
> >>
> >>
> >> _______________________________________________
> >> LLVM Developers mailing list
> >> llvm-dev at lists.llvm.org
> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>
>
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