* [PATCH bpf] selftests/bpf: Fix massive output from test_maps
@ 2020-08-26 8:17 Jesper Dangaard Brouer
2020-08-26 8:29 ` Jesper Dangaard Brouer
0 siblings, 1 reply; 3+ messages in thread
From: Jesper Dangaard Brouer @ 2020-08-26 8:17 UTC (permalink / raw)
To: Jesper Dangaard Brouer, bpf
Cc: Daniel Borkmann, Alexei Starovoitov, ykaliuta, zsun, vkabatov
When stdout output from the selftests tool 'test_maps' gets redirected
into e.g file or pipe, then the output lines increase a lot (from 21
to 33949 lines). This is caused by the printf that happens before the
fork() call, and there are user-space buffered printf data that seems
to be duplicated into the forked process.
To fix this fflush() stdout before the fork loop in __run_parallel().
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---
tools/testing/selftests/bpf/test_maps.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
index 754cf611723e..0d92ebcb335d 100644
--- a/tools/testing/selftests/bpf/test_maps.c
+++ b/tools/testing/selftests/bpf/test_maps.c
@@ -1274,6 +1274,8 @@ static void __run_parallel(unsigned int tasks,
pid_t pid[tasks];
int i;
+ fflush(stdout);
+
for (i = 0; i < tasks; i++) {
pid[i] = fork();
if (pid[i] == 0) {
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH bpf] selftests/bpf: Fix massive output from test_maps
2020-08-26 8:17 [PATCH bpf] selftests/bpf: Fix massive output from test_maps Jesper Dangaard Brouer
@ 2020-08-26 8:29 ` Jesper Dangaard Brouer
2020-08-28 12:00 ` Daniel Borkmann
0 siblings, 1 reply; 3+ messages in thread
From: Jesper Dangaard Brouer @ 2020-08-26 8:29 UTC (permalink / raw)
To: Jesper Dangaard Brouer, bpf
Cc: Daniel Borkmann, Alexei Starovoitov, ykaliuta, zsun, vkabatov
On Wed, 26 Aug 2020 10:17:36 +0200
Jesper Dangaard Brouer <brouer@redhat.com> wrote:
> When stdout output from the selftests tool 'test_maps' gets redirected
> into e.g file or pipe, then the output lines increase a lot (from 21
> to 33949 lines). This is caused by the printf that happens before the
> fork() call, and there are user-space buffered printf data that seems
> to be duplicated into the forked process.
>
> To fix this fflush() stdout before the fork loop in __run_parallel().
>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Fixes: 1a97cf1fe503 ("selftests/bpf: speedup test_maps")
I forgot to add the fixes line to the patch, I hope patchwork[1] will
pick it up for maintainers.
[1] http://patchwork.ozlabs.org/project/netdev/patch/159842985651.1050885.2154399297503372406.stgit@firesoul/
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH bpf] selftests/bpf: Fix massive output from test_maps
2020-08-26 8:29 ` Jesper Dangaard Brouer
@ 2020-08-28 12:00 ` Daniel Borkmann
0 siblings, 0 replies; 3+ messages in thread
From: Daniel Borkmann @ 2020-08-28 12:00 UTC (permalink / raw)
To: Jesper Dangaard Brouer, bpf
Cc: Daniel Borkmann, Alexei Starovoitov, ykaliuta, zsun, vkabatov
On 8/26/20 10:29 AM, Jesper Dangaard Brouer wrote:
> On Wed, 26 Aug 2020 10:17:36 +0200
> Jesper Dangaard Brouer <brouer@redhat.com> wrote:
>
>> When stdout output from the selftests tool 'test_maps' gets redirected
>> into e.g file or pipe, then the output lines increase a lot (from 21
>> to 33949 lines). This is caused by the printf that happens before the
>> fork() call, and there are user-space buffered printf data that seems
>> to be duplicated into the forked process.
>>
>> To fix this fflush() stdout before the fork loop in __run_parallel().
>>
>> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
>
> Fixes: 1a97cf1fe503 ("selftests/bpf: speedup test_maps")
>
> I forgot to add the fixes line to the patch, I hope patchwork[1] will
> pick it up for maintainers.
It won't but I've just added it manually. Applied, thanks!
> [1] http://patchwork.ozlabs.org/project/netdev/patch/159842985651.1050885.2154399297503372406.stgit@firesoul/
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-08-26 8:17 [PATCH bpf] selftests/bpf: Fix massive output from test_maps Jesper Dangaard Brouer
2020-08-26 8:29 ` Jesper Dangaard Brouer
2020-08-28 12:00 ` Daniel Borkmann
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