Re: Scheduler benchmarks
Em Wed, Aug 19, 2020 at 03:46:06PM +0530, Muni Sekhar escreveu: > On Tue, Aug 18, 2020 at 11:45 PM peter enderborg > wrote: > > On 8/18/20 7:53 PM, Muni Sekhar wrote: > > > On Tue, Aug 18, 2020 at 11:06 PM Greg KH wrote: > > >> On Tue, Aug 18, 2020 at 11:01:35PM +0530, Muni Sekhar wrote: > > >>> On Tue, Aug 18, 2020 at 10:44 PM Greg KH wrote: > > >> Those are _very_ different kernel versions, with many years and tens of > > >> thousands of different changes between them. > > >> > > >> Hopefully the newer kernel is faster, so just stick with that :) > > > But unfortunately the newer kernel is very slow, that is the reason > > > for starting this investigation :) > > > Any type of help, and guidelines to dive deeper will be highly > > > appreciated. > > > > On the 4.4 kernel you dont have > > > > +CONFIG_RETPOLINE=y > > +CONFIG_INTEL_RDT=y > Thanks! That is helpful. Yes, I see 4.4 kernel don't have the above > two config options. > What analysis can be done to narrow down the root cause? > Any example of reference could be helpful to understand. This made me remember Lisbon: http://vger.kernel.org/~acme/perf/bpf-is-eating-the-world-dont-you-see-lpc-lisbon-2019/#/8/2 Greg was there when this slide was first shown... ;-) Look at the icache misses when the kernel is entered (syscall entry). Then add this to the kernel command line: "nospectre_v1 nospectre_v2" And see what happens: http://vger.kernel.org/~acme/perf/bpf-is-eating-the-world-dont-you-see-lpc-lisbon-2019/#/8/3 So using these (and any new ones related to disabling hardware flaw mitigation) maybe a way to analyse this, if you haven't figured this out yet, sorry for the huge delay in replying 8-) - Arnaldo > > > > And your base is very different two. > > > > Try to use mainline on both system and see. > > > > You can also use the same base kernel version from ubuntu and > > > > run your test. > > > > > > >> greg k-h > > > > > > > > > > > -- > Thanks, > Sekhar -- - Arnaldo ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: [tools/perf] perf test LLVM failure on 4.9
Em Tue, Jan 23, 2018 at 06:07:25PM +0530, Pintu Kumar escreveu:
> Hi All,
>
> I am verifying all perf tests on Ubuntu-16 x86-64 platform using the
> kernel version 4.9.20.
> I have installed several others packages including: clang, llvm
>
> But, when I run 'perf test' I get some FAILURE.
> Specially, 'perf test LLVM' is failing.
Wang, could you please take a look? I'll be traveling this week, so
probably will not have time for trying to work on this.
- Arnaldo
> Please check the below error logs:
>
>
> # perf test LLVM
> 35: Test LLVM searching and compiling:
> 35.1: Basic BPF llvm compiling test : FAILED!
> 35.2: Test kbuild searching : Skip
> 35.3: Compile source for BPF prologue generation test: Skip
> 35.4: Compile source for BPF relocation test : Skip
>
>
> When I run with -v I get this:
>
> -
> # perf test -v LLVM
> 35: Test LLVM searching and compiling:
> 35.1: Basic BPF llvm compiling test :
> --- start ---
> test child forked, pid 3304
> Unablt to get kernel version from uname '4.9--amd-x86-64'
> WARNING:unable to get correct kernel building directory.
> Hint: Set correct kbuild directory using 'kbuild-dir' option in [llvm]
> section of ~/.perfconfig or set it to "" to suppress kbuild
> detection.
>
> Unablt to get kernel version from uname '4.9--amd-x86-64'
>
>
> int _version SEC("version") = LINUX_VERSION_CODE;
> ' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS
> -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS
> $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign
> -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o
> -
> libbpf: 2129190-4a0 doesn't provide kernel version
> Failed to parse test case 'Basic BPF llvm compiling test'
> test child finished with -1
> end
> Test LLVM searching and compiling subtest 0: FAILED!
> -
>
>
> Basic BPF LLVM compiling test is failing.
> It reports that bpf could not able to read the kernel version from uname.
> Is it because of this that 'perf test LLVM' is failing ?
>
> My uname says:
> 4.9--amd-x86-64
>
> My kernel version is: 4.9.20 (from Makefile)
>
> So, I dont think there is any problem with kernel version.
>
> If any body have come across this problem please let me know how to
> resolve this issue.
>
>
>
> Thank You!
>
> Regards,
> Pintu
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