[DTrace-devel] [PATCH] test: Bump timeouts up for bpflogsize tests

[Kris Van Hees]

On Thu, Feb 29, 2024 at 07:08:28PM -0500, Eugene Loh via DTrace-devel wrote:
> The tests run a script that looks like this:
> 
> BEGIN
> {
>         x = 1;
>         @ = quantize(x);
>         @ = quantize(x);
>         @ = quantize(x);
>         [this "quantize" line appears a total of 2000 times]
>         @ = quantize(x);
>         @ = quantize(x);
>         @ = quantize(x);
>         exit(0);
> }
> 
> That is, it's an intentionally large program.
> 
> In dt_bpf.c, we try loading some tiny test programs for have_helpers(). 
> They do not take much time.  But we also call dt_bpf_load_prog() to load the
> big BEGIN program... twice!  (The first time fails, so we call again but now
> with a log file enabled.)  On an OL8 x86 VM, I get about 0.05 for the first
> dt_bpf_prog_load() call (no log file) and about 0.35 secs for the second
> dt_bpf_prog_load() call (with log file).  (As you probably know,
> bpf_load_prog() calls bpf_prog_load().  Confusing naming.) So, the test does
> not take much time.
> 
> On an OL9 x86 VM, however, each bpf_prog_load() call takes about 5 seconds. 
> While it allows for retries, the long duration is not due to retries:  a
> single bpf(BPF_PROG_LOAD, ...) system call is taking that long, apparently
> due to the size of the program being loaded.  Smaller programs are much
> faster.

Oh my.  That is quite long - this might be something Alan might be interested
in because that seems to be prohibitively slow.  I wonder whether it is the
verifier taking that long or some other processing.

> The test incurs this operation multiple times.  Add to that some other
> overheads, and soon you're bumping up against the timeout.
> 
> On 2/29/24 13:19, Kris Van Hees wrote:
> > Do we have any idea why it is a timeout issue?  Perhaps you could try adding
> > some timing info (just for debugging this) to see how long the bpf syscalls
> > take, to see if it is a delay at the kernel side or elsewhere?
> > 
> > On Wed, Feb 28, 2024 at 07:29:11PM -0500, eugene.loh--- via DTrace-devel wrote:
> > > From: Eugene Loh <eugene.loh at oracle.com>
> > > 
> > > Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
> > > ---
> > >   test/unittest/options/tst.bpflogsize-cmdline.sh | 3 ++-
> > >   test/unittest/options/tst.bpflogsize-pragma.sh  | 3 ++-
> > >   2 files changed, 4 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/test/unittest/options/tst.bpflogsize-cmdline.sh b/test/unittest/options/tst.bpflogsize-cmdline.sh
> > > index 2d85e12c..509f9d07 100755
> > > --- a/test/unittest/options/tst.bpflogsize-cmdline.sh
> > > +++ b/test/unittest/options/tst.bpflogsize-cmdline.sh
> > > @@ -1,10 +1,11 @@
> > >   #!/bin/bash
> > >   #
> > >   # Oracle Linux DTrace.
> > > -# Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
> > > +# Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
> > >   # Licensed under the Universal Permissive License v 1.0 as shown at
> > >   # http://oss.oracle.com/licenses/upl.
> > >   #
> > > +# @@timeout: 100
> > >   dtrace=$1
> > > diff --git a/test/unittest/options/tst.bpflogsize-pragma.sh b/test/unittest/options/tst.bpflogsize-pragma.sh
> > > index 5d03b5f7..3dea3dd4 100755
> > > --- a/test/unittest/options/tst.bpflogsize-pragma.sh
> > > +++ b/test/unittest/options/tst.bpflogsize-pragma.sh
> > > @@ -1,10 +1,11 @@
> > >   #!/bin/bash
> > >   #
> > >   # Oracle Linux DTrace.
> > > -# Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
> > > +# Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
> > >   # Licensed under the Universal Permissive License v 1.0 as shown at
> > >   # http://oss.oracle.com/licenses/upl.
> > >   #
> > > +# @@timeout: 100
> > >   dtrace=$1
> > > -- 
> > > 2.18.4
> > > 
> > > 
> > > _______________________________________________
> > > DTrace-devel mailing list
> > > DTrace-devel at oss.oracle.com
> > > https://oss.oracle.com/mailman/listinfo/dtrace-devel
> 
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