From mboxrd@z Thu Jan 1 00:00:00 1970 From: Akira Yokosawa Subject: Re: Some -serious- BPF-related litmus tests Date: Wed, 27 May 2020 07:23:24 +0900 Message-ID: References: <20200522003850.GA32698@paulmck-ThinkPad-P72> <20200522094407.GK325280@hirez.programming.kicks-ass.net> <20200522143201.GB32434@rowland.harvard.edu> <20200522174352.GJ2869@paulmck-ThinkPad-P72> <006e2bc6-7516-1584-3d8c-e253211c157e@fb.com> <69ed3604-4275-d73e-a5d6-2b70dd877104@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389382AbgEZWXc (ORCPT ); Tue, 26 May 2020 18:23:32 -0400 In-Reply-To: Content-Language: en-US Sender: linux-arch-owner@vger.kernel.org List-ID: To: Andrii Nakryiko Cc: luc.maranget@inria.fr, Andrii Nakryiko , "Paul E . McKenney" , Alan Stern , Peter Zijlstra , parri.andrea@gmail.com, will@kernel.org, Boqun Feng , npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk, dlustig@nvidia.com, Joel Fernandes , open list , linux-arch@vger.kernel.org On Tue, 26 May 2020 13:15:49 -0700, Andrii Nakryiko wrote: > On Tue, May 26, 2020 at 3:50 AM Akira Yokosawa wrote= : >> >> On Mon, 25 May 2020 16:31:05 -0700, Andrii Nakryiko wrote: >>> On Mon, May 25, 2020 at 3:01 PM Akira Yokosawa wro= te: >>>> >> [...] >>>> Yes, that should work. >>> >>> Ok, assigning to zero didn't work (it still complained about >>> uninitialized read), but using a separate int *lenFail to assign to >>> rLenPtr worked. Curiously, if I used rLenPtr =3D len1; in error case,= it >>> actually takes a bit more time to verify. >>> >>> So I've converted everything else as you suggested. I compiled latest= >>> herd7 and it doesn't produce any warnings. But it's also extremely >>> slow, compared to the herd7 that I get by default. Validating simple >>> 1p1c cases takes about 2.5x times longer (0.03s vs 0.07), but trying >>> to validate 2p1c case, which normally validates in 42s (unbounded) an= d >>> 110s (bounded), it took more than 20 minutes and hasn't finished, >>> before I gave up. So I don't know what's going on there... >> >> herdtools7 has recently been heavily restructured. >> On the performance regression, I must defer to Luc. >> >> Luc, do you have any idea? >> >>> >>> As for klitmus7, I managed to generate everything without warnings, >>> but couldn't make it build completely due to: >>> >>> $ make >>> make -C /lib/modules/5.6.13-01802-g938d64da97c6/build/ >> >> So you are on Linux 5.6.x which requires cutting-edge klitmus7. >> >=20 > Right, so I retried with the klitmus7 built from sources: >=20 > $ klitmus7 -version >=20 > 7.55+01(dev) >=20 > Still can't compile, though task_struct problem went away, proc_ops > error is still present: >=20 > $ make > grep: /lib/modules/5.7.0-rc5-02014-gb16540c748e9/build/include/linux/pr= oc_fs.h: > No such file or directory Hmm, have you installed kernel-headers on your system? You are now on Linux 5.7-rc5 based system... Thanks, Akira > make -C /lib/modules/5.7.0-rc5-02014-gb16540c748e9/build/ > M=3D/home/andriin/local/linux-trees/tools/memory-model/mymodules module= s > make[1]: Entering directory `/data/users/andriin/linux-build/fb-config'= > make[2]: Entering directory `/data/users/andriin/linux-build/default-x8= 6_64' > grep: /lib/modules/5.7.0-rc5-02014-gb16540c748e9/build/include/linux/pr= oc_fs.h: > No such file or directory > CC [M] /home/andriin/local/linux-trees/tools/memory-model/mymodules/= litmus000.o > /home/andriin/local/linux-trees/tools/memory-model/mymodules/litmus000.= c: > In function =E2=80=98litmus_init=E2=80=99: > /home/andriin/local/linux-trees/tools/memory-model/mymodules/litmus000.= c:621:67: > error: passing argument 4 of =E2=80=98proc_create=E2=80=99 from incompa= tible pointer > type [-Werror=3Dincompatible-pointer-types] > struct proc_dir_entry *litmus_pde =3D > proc_create("litmus",0,NULL,&litmus_proc_ops); >=20 > ^~~~~~~~~~~~~~~~ > In file included from > /home/andriin/local/linux-trees/tools/memory-model/mymodules/litmus000.= c:15: > /data/users/andriin/linux/include/linux/proc_fs.h:79:24: note: > expected =E2=80=98const struct proc_ops *=E2=80=99 but argument is of t= ype =E2=80=98const > struct file_operations *=E2=80=99 > struct proc_dir_entry *proc_create(const char *name, umode_t mode, > struct proc_dir_entry *parent, const struct proc_ops *proc_ops); > ^~~~~~~~~~~ > cc1: some warnings being treated as errors > make[3]: *** [/home/andriin/local/linux-trees/tools/memory-model/mymodu= les/litmus000.o] > Error 1 > make[2]: *** [/home/andriin/local/linux-trees/tools/memory-model/mymodu= les] > Error 2 > make[2]: Leaving directory `/data/users/andriin/linux-build/default-x86= _64' > make[1]: *** [sub-make] Error 2 > make[1]: Leaving directory `/data/users/andriin/linux-build/fb-config' > make: *** [all] Error 2 >=20 > Don't know if I'm missing some headers or whatever. >=20 >>> M=3D/home/andriin/local/linux-trees/tools/memory-model/mymodules modu= les >>> make[1]: Entering directory `/data/users/andriin/linux-build/fb-confi= g' >>> make[2]: Entering directory `/data/users/andriin/linux-build/default-= x86_64' >>> CC [M] /home/andriin/local/linux-trees/tools/memory-model/mymodule= s/litmus000.o >>> /home/andriin/local/linux-trees/tools/memory-model/mymodules/litmus00= 0.c: >>> In function =E2=80=98zyva=E2=80=99: >>> /home/andriin/local/linux-trees/tools/memory-model/mymodules/litmus00= 0.c:507:12: >>> warning: ISO C90 forbids variable length array =E2=80=98th=E2=80=99 [= -Wvla] >>> struct task_struct *th[nth]; >>> ^~~~~~~~~~~ >>> /home/andriin/local/linux-trees/tools/memory-model/mymodules/litmus00= 0.c: >>> In function =E2=80=98litmus_init=E2=80=99: >>> /home/andriin/local/linux-trees/tools/memory-model/mymodules/litmus00= 0.c:605:67: >>> error: passing argument 4 of =E2=80=98proc_create=E2=80=99 from incom= patible pointer >>> type [-Werror=3Dincompatible-pointer-types] >>> struct proc_dir_entry *litmus_pde =3D >>> proc_create("litmus",0,NULL,&litmus_proc_fops); >>> >>> ^~~~~~~~~~~~~~~~~ >>> In file included from >>> /home/andriin/local/linux-trees/tools/memory-model/mymodules/litmus00= 0.c:15: >>> /data/users/andriin/linux-fb/include/linux/proc_fs.h:64:24: note: >>> expected =E2=80=98const struct proc_ops *=E2=80=99 but argument is of= type =E2=80=98const >>> struct file_operations *=E2=80=99 >>> struct proc_dir_entry *proc_create(const char *name, umode_t mode, >>> struct proc_dir_entry *parent, const struct proc_ops *proc_ops); >>> ^~~~~~~~~~~ >>> cc1: some warnings being treated as errors >>> make[3]: *** [/home/andriin/local/linux-trees/tools/memory-model/mymo= dules/litmus000.o] >>> Error 1 >>> make[2]: *** [/home/andriin/local/linux-trees/tools/memory-model/mymo= dules] >>> Error 2 >>> make[2]: Leaving directory `/data/users/andriin/linux-build/default-x= 86_64' >>> make[1]: *** [sub-make] Error 2 >>> make[1]: Leaving directory `/data/users/andriin/linux-build/fb-config= ' >>> make: *** [all] Error 2 >>> >> >> These errors suggest the klitmus7 you used is version 7.52 or some suc= h. >> You said you have built herd7 from the source. Have you also built kl= itmus7? >=20 > I did, but it wasn't in the PATH. I retried with latest klitmus7 and > still run into problems. >=20 >> >> The up-to-date klitmus7 should generate code compatible with Linux 5.6= =2Ex. >> >> Could you try with the latest one? >> >> Thanks, Akira >> >>> >>> But at least it doesn't complain about atomic_t anymore. So anyways, >>> I'm going to post updated litmus tests separately from BPF ringbuf >>> patches, because Documentation/litmus-tests is not yet present in >>> bpf-next. >>> >>>> >>>> You can find a basic introduction of klitmus7 in tools/memory-model/= README. >>>> >>>> Thanks, Akira >>>> >>>>> >>>>>> >>>>>> Please note that if you are on Linux 5.6 (or later), you need an u= p-to-date >>>>>> klitmus7 due to a change in kernel API. >>>>>> >>>>>> Any question is welcome! >>>>>> >>>>>> Thanks, Akira >>>>>> >>> >>> [...] >>> >>