| Message ID | 15d7646940fcbb8477b1be1aa11a5d5485d10b48.1691125344.git.geliang.tang@suse.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | bpf: Force to MPTCP | expand |
On 8/3/23 10:07 PM, Geliang Tang wrote: > Use rand() to generate a random netns name instead of using the fixed > name "mptcp_ns" for every test. > > By doing that, we can re-launch the test even if there was an issue > removing the previous netns or if by accident, a netns with this generic > name already existed on the system. > > Note that using a different name each will also help adding more > subtests in future commits. I run test_progs repeatedly without rebooting qemu to save time. If there is a test did not clean up its netns, I would rather uncover it earlier and fix it instead. Randomizing the name is hiding the issue and does not help to uncover the broken test sooner. Although this change is to mptcp test alone, this could be referred in other future tests. afaik, I don't remember bpf CI ever run into a test failure because the picked name had already been used by the system. It seems you ran into this issue a lot with the mptcp test in your setup. Could you explain a little more?
On Fri, Aug 04, 2023 at 05:23:32PM -0700, Martin KaFai Lau wrote: > On 8/3/23 10:07 PM, Geliang Tang wrote: > > Use rand() to generate a random netns name instead of using the fixed > > name "mptcp_ns" for every test. > > > > By doing that, we can re-launch the test even if there was an issue > > removing the previous netns or if by accident, a netns with this generic > > name already existed on the system. > > > > Note that using a different name each will also help adding more > > subtests in future commits. Hi Martin, I tried to run mptcp tests simultaneously, and got "Cannot create namespace file "/var/run/netns/mptcp_ns": File exists" errors sometimes. So I add this patch to fix it. It's easy to reproduce, just run this commands in multiple terminals: > for i in `seq 1 100`; do sudo ./test_progs -t mptcp; done > > I run test_progs repeatedly without rebooting qemu to save time. If there is > a test did not clean up its netns, I would rather uncover it earlier and fix > it instead. Randomizing the name is hiding the issue and does not help to > uncover the broken test sooner. Although this change is to mptcp test alone, > this could be referred in other future tests. I added "ip netns show" after "ip netns del" in v12 to check if there is a test did not clean up its netns. Thanks, -Geliang > > afaik, I don't remember bpf CI ever run into a test failure because the > picked name had already been used by the system. It seems you ran into this > issue a lot with the mptcp test in your setup. Could you explain a little > more?
On 8/6/23 11:40 PM, Geliang Tang wrote: > On Fri, Aug 04, 2023 at 05:23:32PM -0700, Martin KaFai Lau wrote: >> On 8/3/23 10:07 PM, Geliang Tang wrote: >>> Use rand() to generate a random netns name instead of using the fixed >>> name "mptcp_ns" for every test. >>> >>> By doing that, we can re-launch the test even if there was an issue >>> removing the previous netns or if by accident, a netns with this generic >>> name already existed on the system. >>> >>> Note that using a different name each will also help adding more >>> subtests in future commits. > > Hi Martin, > > I tried to run mptcp tests simultaneously, and got "Cannot create > namespace file "/var/run/netns/mptcp_ns": File exists" errors sometimes. > So I add this patch to fix it. > > It's easy to reproduce, just run this commands in multiple terminals: > > for i in `seq 1 100`; do sudo ./test_progs -t mptcp; done Not only the "-t mptcp" test. Other tests in test_progs also don't support running parallel in multiple terminals. Does it really help to test the bpf part of the prog_tests/mptcp.c test by running like this? If it wants to exercise the other mptcp networking specific code like this, a separate mptcp test is needed outside of test_progs and it won't be run in the bpf CI. If you agree, can you please avoid introducing unnecessary randomness to the test_progs where bpf CI and most users don't run in this way? Also, please don't resend the patches too fast until the discussion is concluded. Please give reasonable time for others to reply. I have a high level question. In LPC 2022 (https://lpc.events/event/16/contributions/1354/), I recall there was idea in using bpf to make other mptcp decision/policy. Any thought and progress on this? This set which only uses bpf to change the protocol feels like an incomplete solution.
On Tue, Aug 08, 2023 at 11:03:30PM -0700, Martin KaFai Lau wrote: > On 8/6/23 11:40 PM, Geliang Tang wrote: > > On Fri, Aug 04, 2023 at 05:23:32PM -0700, Martin KaFai Lau wrote: > > > On 8/3/23 10:07 PM, Geliang Tang wrote: > > > > Use rand() to generate a random netns name instead of using the fixed > > > > name "mptcp_ns" for every test. > > > > > > > > By doing that, we can re-launch the test even if there was an issue > > > > removing the previous netns or if by accident, a netns with this generic > > > > name already existed on the system. > > > > > > > > Note that using a different name each will also help adding more > > > > subtests in future commits. > > > > Hi Martin, > > > > I tried to run mptcp tests simultaneously, and got "Cannot create > > namespace file "/var/run/netns/mptcp_ns": File exists" errors sometimes. > > So I add this patch to fix it. > > > > It's easy to reproduce, just run this commands in multiple terminals: > > > for i in `seq 1 100`; do sudo ./test_progs -t mptcp; done > > Not only the "-t mptcp" test. Other tests in test_progs also don't support > running parallel in multiple terminals. Does it really help to test the bpf > part of the prog_tests/mptcp.c test by running like this? If it wants to > exercise the other mptcp networking specific code like this, a separate > mptcp test is needed outside of test_progs and it won't be run in the bpf > CI. > > If you agree, can you please avoid introducing unnecessary randomness to the > test_progs where bpf CI and most users don't run in this way? Thanks Martin. Sure, I agree. Let's drop this patch. > > Also, please don't resend the patches too fast until the discussion is > concluded. Please give reasonable time for others to reply. Sure. Please give me a clear reminder next time that it's time to resend a new version of the patches. > > I have a high level question. In LPC 2022 > (https://lpc.events/event/16/contributions/1354/), I recall there was idea > in using bpf to make other mptcp decision/policy. Any thought and progress > on this? This set which only uses bpf to change the protocol feels like an > incomplete solution. We are implementing MPTCP packet scheduler using BPF. Patches aren't sent to BPF mail list yet, only temporarily on our mptcp repo[1]. Here are the patches: selftests/bpf: Add bpf_burst test selftests/bpf: Add bpf_burst scheduler bpf: Export more bpf_burst related functions selftests/bpf: Add bpf_red test selftests/bpf: Add bpf_red scheduler selftests/bpf: Add bpf_rr test selftests/bpf: Add bpf_rr scheduler selftests/bpf: Add bpf_bkup test selftests/bpf: Add bpf_bkup scheduler selftests/bpf: Add bpf_first test selftests/bpf: Add bpf_first scheduler selftests/bpf: Add bpf scheduler test selftests/bpf: add two mptcp netns helpers selftests/bpf: use random netns name for mptcp selftests/bpf: Add mptcp sched structs bpf: Add bpf_mptcp_sched_kfunc_set bpf: Add bpf_mptcp_sched_ops If you could take a look at these patches in advance, I would greatly appreciate it. Any feedback is welcome. [1] https://github.com/multipath-tcp/mptcp_net-next.git -Geliang >
On 8/9/23 1:19 AM, Geliang Tang wrote: > On Tue, Aug 08, 2023 at 11:03:30PM -0700, Martin KaFai Lau wrote: >> On 8/6/23 11:40 PM, Geliang Tang wrote: >>> On Fri, Aug 04, 2023 at 05:23:32PM -0700, Martin KaFai Lau wrote: >>>> On 8/3/23 10:07 PM, Geliang Tang wrote: >>>>> Use rand() to generate a random netns name instead of using the fixed >>>>> name "mptcp_ns" for every test. >>>>> >>>>> By doing that, we can re-launch the test even if there was an issue >>>>> removing the previous netns or if by accident, a netns with this generic >>>>> name already existed on the system. >>>>> >>>>> Note that using a different name each will also help adding more >>>>> subtests in future commits. >>> >>> Hi Martin, >>> >>> I tried to run mptcp tests simultaneously, and got "Cannot create >>> namespace file "/var/run/netns/mptcp_ns": File exists" errors sometimes. >>> So I add this patch to fix it. >>> >>> It's easy to reproduce, just run this commands in multiple terminals: >>> > for i in `seq 1 100`; do sudo ./test_progs -t mptcp; done >> >> Not only the "-t mptcp" test. Other tests in test_progs also don't support >> running parallel in multiple terminals. Does it really help to test the bpf >> part of the prog_tests/mptcp.c test by running like this? If it wants to >> exercise the other mptcp networking specific code like this, a separate >> mptcp test is needed outside of test_progs and it won't be run in the bpf >> CI. >> >> If you agree, can you please avoid introducing unnecessary randomness to the >> test_progs where bpf CI and most users don't run in this way? > > Thanks Martin. Sure, I agree. Let's drop this patch. Thanks you. >> I have a high level question. In LPC 2022 >> (https://lpc.events/event/16/contributions/1354/), I recall there was idea >> in using bpf to make other mptcp decision/policy. Any thought and progress >> on this? This set which only uses bpf to change the protocol feels like an >> incomplete solution. > > We are implementing MPTCP packet scheduler using BPF. Patches aren't > sent to BPF mail list yet, only temporarily on our mptcp repo[1]. > > Here are the patches: > > selftests/bpf: Add bpf_burst test > selftests/bpf: Add bpf_burst scheduler > bpf: Export more bpf_burst related functions > selftests/bpf: Add bpf_red test > selftests/bpf: Add bpf_red scheduler > selftests/bpf: Add bpf_rr test > selftests/bpf: Add bpf_rr scheduler > selftests/bpf: Add bpf_bkup test > selftests/bpf: Add bpf_bkup scheduler > selftests/bpf: Add bpf_first test > selftests/bpf: Add bpf_first scheduler > selftests/bpf: Add bpf scheduler test > selftests/bpf: add two mptcp netns helpers > selftests/bpf: use random netns name for mptcp > selftests/bpf: Add mptcp sched structs > bpf: Add bpf_mptcp_sched_kfunc_set > bpf: Add bpf_mptcp_sched_ops > > If you could take a look at these patches in advance, I would greatly > appreciate it. Any feedback is welcome. > > [1] > https://github.com/multipath-tcp/mptcp_net-next.git Thanks for sharing. I did not go into the details. iiuc, the scheduler is specific to a namespace. Do you see if it is useful to have more finer control like depending on what IP address it is connected to? BPF policy is usually found more useful to have finer policy control than global or per-netns. The same question goes for the fmod_ret here in this patch. The progs/mptcpify.c selftest is as good as upgrading all TCP connections. Is it your only use case and no need for finer selection?
On Thu, Aug 10, 2023 at 10:53:38PM -0700, Martin KaFai Lau wrote: > On 8/9/23 1:19 AM, Geliang Tang wrote: > > On Tue, Aug 08, 2023 at 11:03:30PM -0700, Martin KaFai Lau wrote: > > > On 8/6/23 11:40 PM, Geliang Tang wrote: > > > > On Fri, Aug 04, 2023 at 05:23:32PM -0700, Martin KaFai Lau wrote: > > > > > On 8/3/23 10:07 PM, Geliang Tang wrote: > > > > > > Use rand() to generate a random netns name instead of using the fixed > > > > > > name "mptcp_ns" for every test. > > > > > > > > > > > > By doing that, we can re-launch the test even if there was an issue > > > > > > removing the previous netns or if by accident, a netns with this generic > > > > > > name already existed on the system. > > > > > > > > > > > > Note that using a different name each will also help adding more > > > > > > subtests in future commits. > > > > > > > > Hi Martin, > > > > > > > > I tried to run mptcp tests simultaneously, and got "Cannot create > > > > namespace file "/var/run/netns/mptcp_ns": File exists" errors sometimes. > > > > So I add this patch to fix it. > > > > > > > > It's easy to reproduce, just run this commands in multiple terminals: > > > > > for i in `seq 1 100`; do sudo ./test_progs -t mptcp; done > > > > > > Not only the "-t mptcp" test. Other tests in test_progs also don't support > > > running parallel in multiple terminals. Does it really help to test the bpf > > > part of the prog_tests/mptcp.c test by running like this? If it wants to > > > exercise the other mptcp networking specific code like this, a separate > > > mptcp test is needed outside of test_progs and it won't be run in the bpf > > > CI. > > > > > > If you agree, can you please avoid introducing unnecessary randomness to the > > > test_progs where bpf CI and most users don't run in this way? > > > > Thanks Martin. Sure, I agree. Let's drop this patch. > > Thanks you. > > > > I have a high level question. In LPC 2022 > > > (https://lpc.events/event/16/contributions/1354/), I recall there was idea > > > in using bpf to make other mptcp decision/policy. Any thought and progress > > > on this? This set which only uses bpf to change the protocol feels like an > > > incomplete solution. > > > > We are implementing MPTCP packet scheduler using BPF. Patches aren't > > sent to BPF mail list yet, only temporarily on our mptcp repo[1]. > > > > Here are the patches: > > > > selftests/bpf: Add bpf_burst test > > selftests/bpf: Add bpf_burst scheduler > > bpf: Export more bpf_burst related functions > > selftests/bpf: Add bpf_red test > > selftests/bpf: Add bpf_red scheduler > > selftests/bpf: Add bpf_rr test > > selftests/bpf: Add bpf_rr scheduler > > selftests/bpf: Add bpf_bkup test > > selftests/bpf: Add bpf_bkup scheduler > > selftests/bpf: Add bpf_first test > > selftests/bpf: Add bpf_first scheduler > > selftests/bpf: Add bpf scheduler test > > selftests/bpf: add two mptcp netns helpers > > selftests/bpf: use random netns name for mptcp > > selftests/bpf: Add mptcp sched structs > > bpf: Add bpf_mptcp_sched_kfunc_set > > bpf: Add bpf_mptcp_sched_ops > > > > If you could take a look at these patches in advance, I would greatly > > appreciate it. Any feedback is welcome. > > > > [1] > > https://github.com/multipath-tcp/mptcp_net-next.git > > Thanks for sharing. I did not go into the details. iiuc, the scheduler is > specific to a namespace. Do you see if it is useful to have more finer > control like depending on what IP address it is connected to? BPF policy is > usually found more useful to have finer policy control than global or > per-netns. > > The same question goes for the fmod_ret here in this patch. The > progs/mptcpify.c selftest is as good as upgrading all TCP connections. Is it > your only use case and no need for finer selection? This per-netns control is just the first step. We do need finer selection. The most ideal mode is to select one app to upgrade it's TCP connections only. So per-cgroup control is much better than per-netns. But we haven't found a good per-cgroup solution yet. Thanks, -Geliang >
On 8/11/23 2:29 AM, Geliang Tang wrote: > On Thu, Aug 10, 2023 at 10:53:38PM -0700, Martin KaFai Lau wrote: >> On 8/9/23 1:19 AM, Geliang Tang wrote: >>> On Tue, Aug 08, 2023 at 11:03:30PM -0700, Martin KaFai Lau wrote: >>>> On 8/6/23 11:40 PM, Geliang Tang wrote: >>>>> On Fri, Aug 04, 2023 at 05:23:32PM -0700, Martin KaFai Lau wrote: >>>>>> On 8/3/23 10:07 PM, Geliang Tang wrote: >>>>>>> Use rand() to generate a random netns name instead of using the fixed >>>>>>> name "mptcp_ns" for every test. >>>>>>> >>>>>>> By doing that, we can re-launch the test even if there was an issue >>>>>>> removing the previous netns or if by accident, a netns with this generic >>>>>>> name already existed on the system. >>>>>>> >>>>>>> Note that using a different name each will also help adding more >>>>>>> subtests in future commits. >>>>> >>>>> Hi Martin, >>>>> >>>>> I tried to run mptcp tests simultaneously, and got "Cannot create >>>>> namespace file "/var/run/netns/mptcp_ns": File exists" errors sometimes. >>>>> So I add this patch to fix it. >>>>> >>>>> It's easy to reproduce, just run this commands in multiple terminals: >>>>> > for i in `seq 1 100`; do sudo ./test_progs -t mptcp; done >>>> >>>> Not only the "-t mptcp" test. Other tests in test_progs also don't support >>>> running parallel in multiple terminals. Does it really help to test the bpf >>>> part of the prog_tests/mptcp.c test by running like this? If it wants to >>>> exercise the other mptcp networking specific code like this, a separate >>>> mptcp test is needed outside of test_progs and it won't be run in the bpf >>>> CI. >>>> >>>> If you agree, can you please avoid introducing unnecessary randomness to the >>>> test_progs where bpf CI and most users don't run in this way? >>> >>> Thanks Martin. Sure, I agree. Let's drop this patch. >> >> Thanks you. >> >>>> I have a high level question. In LPC 2022 >>>> (https://lpc.events/event/16/contributions/1354/), I recall there was idea >>>> in using bpf to make other mptcp decision/policy. Any thought and progress >>>> on this? This set which only uses bpf to change the protocol feels like an >>>> incomplete solution. >>> >>> We are implementing MPTCP packet scheduler using BPF. Patches aren't >>> sent to BPF mail list yet, only temporarily on our mptcp repo[1]. >>> >>> Here are the patches: >>> >>> selftests/bpf: Add bpf_burst test >>> selftests/bpf: Add bpf_burst scheduler >>> bpf: Export more bpf_burst related functions >>> selftests/bpf: Add bpf_red test >>> selftests/bpf: Add bpf_red scheduler >>> selftests/bpf: Add bpf_rr test >>> selftests/bpf: Add bpf_rr scheduler >>> selftests/bpf: Add bpf_bkup test >>> selftests/bpf: Add bpf_bkup scheduler >>> selftests/bpf: Add bpf_first test >>> selftests/bpf: Add bpf_first scheduler >>> selftests/bpf: Add bpf scheduler test >>> selftests/bpf: add two mptcp netns helpers >>> selftests/bpf: use random netns name for mptcp >>> selftests/bpf: Add mptcp sched structs >>> bpf: Add bpf_mptcp_sched_kfunc_set >>> bpf: Add bpf_mptcp_sched_ops >>> >>> If you could take a look at these patches in advance, I would greatly >>> appreciate it. Any feedback is welcome. >>> >>> [1] >>> https://github.com/multipath-tcp/mptcp_net-next.git >> >> Thanks for sharing. I did not go into the details. iiuc, the scheduler is >> specific to a namespace. Do you see if it is useful to have more finer >> control like depending on what IP address it is connected to? BPF policy is >> usually found more useful to have finer policy control than global or >> per-netns. >> >> The same question goes for the fmod_ret here in this patch. The >> progs/mptcpify.c selftest is as good as upgrading all TCP connections. Is it >> your only use case and no need for finer selection? > > This per-netns control is just the first step. We do need finer selection. The > most ideal mode is to select one app to upgrade it's TCP connections only. So > per-cgroup control is much better than per-netns. But we haven't found a good > per-cgroup solution yet. Selecting an app or cgroup can sort of be done by getting the current task or current cgroup (there is helper to do that). I am imagining eventually it will want to decide the protocol upgrade and/or the mptcp-scheduler when the destination IP is decided. This fmod_ret upgrade for all acts like a global knob (sysctl) and feels like a hack or at least incomplete. However, I also don't see a clean way to do that for now in the current shape. Please respin another revision to address the earlier selftest comment on the netns name. Thanks.
diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c index cd0c42fff7c0..4ccca3d39a8f 100644 --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c @@ -7,7 +7,7 @@ #include "network_helpers.h" #include "mptcp_sock.skel.h" -#define NS_TEST "mptcp_ns" +char NS_TEST[32]; #ifndef TCP_CA_NAME_MAX #define TCP_CA_NAME_MAX 16 @@ -147,6 +147,8 @@ static void test_base(void) if (!ASSERT_GE(cgroup_fd, 0, "test__join_cgroup")) return; + srand(time(NULL)); + snprintf(NS_TEST, sizeof(NS_TEST), "mptcp_ns_%d", rand()); SYS(fail, "ip netns add %s", NS_TEST); SYS(fail, "ip -net %s link set dev lo up", NS_TEST);