| Message ID | 1682414197-13173-1-git-send-email-alan.maguire@oracle.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | tracing: support > 8 byte filter predicates | expand |
On Tue, 25 Apr 2023 10:16:34 +0100 Alan Maguire <alan.maguire@oracle.com> wrote: > For cases like IPv6 addresses, having a means to supply tracing > predicates for fields with more than 8 bytes would be convenient. > This series provides a simple way to support this by allowing > simple ==, != memory comparison with the predicate supplied when > the size of the field exceeds 8 bytes. For example, to trace > ::1, the predicate > > "dst == 0x00000000000000000000000000000001" > > ..could be used. Nice! And I also would like to use something like "dst == ipv6(::1)" because it seems easy to make a mistake on the number of zeros. Can we add such type casting feature to the filter? Thank you, > > Patch 1 provides the support for > 8 byte fields via a memcmp()-style > predicate. Patch 2 adds tests for filter predicates, and patch 3 > documents the fact that for > 8 bytes. only == and != are supported. > > Changes since RFC [1]: > > - originally a fix was intermixed with the new functionality as > patch 1 in series [1]; the fix landed separately > - small tweaks to how filter predicates are defined via fn_num as > opposed to via fn directly > > [1] https://lore.kernel.org/lkml/1659910883-18223-1-git-send-email-alan.maguire@oracle.com/ > > Alan Maguire (3): > tracing: support > 8 byte array filter predicates > selftests/ftrace: add test coverage for filter predicates > tracing: document > 8 byte numeric filtering support > > Documentation/trace/events.rst | 9 +++ > kernel/trace/trace_events_filter.c | 55 +++++++++++++++- > .../selftests/ftrace/test.d/event/filter.tc | 62 +++++++++++++++++++ > 3 files changed, 125 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/ftrace/test.d/event/filter.tc > > -- > 2.31.1 >
On 25/04/2023 15:32, Masami Hiramatsu (Google) wrote: > On Tue, 25 Apr 2023 10:16:34 +0100 > Alan Maguire <alan.maguire@oracle.com> wrote: > >> For cases like IPv6 addresses, having a means to supply tracing >> predicates for fields with more than 8 bytes would be convenient. >> This series provides a simple way to support this by allowing >> simple ==, != memory comparison with the predicate supplied when >> the size of the field exceeds 8 bytes. For example, to trace >> ::1, the predicate >> >> "dst == 0x00000000000000000000000000000001" >> >> ..could be used. > > Nice! > And I also would like to use something like "dst == ipv6(::1)" because > it seems easy to make a mistake on the number of zeros. > > Can we add such type casting feature to the filter? > that's a great idea; what would be the most consistent ftrace syntax for this do you think? I noticed that hist triggers append a modifier to the field name so would something like "dst.ipv6 == ::1" make sense maybe? Thanks! Alan > Thank you, > >> >> Patch 1 provides the support for > 8 byte fields via a memcmp()-style >> predicate. Patch 2 adds tests for filter predicates, and patch 3 >> documents the fact that for > 8 bytes. only == and != are supported. >> >> Changes since RFC [1]: >> >> - originally a fix was intermixed with the new functionality as >> patch 1 in series [1]; the fix landed separately >> - small tweaks to how filter predicates are defined via fn_num as >> opposed to via fn directly >> >> [1] https://lore.kernel.org/lkml/1659910883-18223-1-git-send-email-alan.maguire@oracle.com/ >> >> Alan Maguire (3): >> tracing: support > 8 byte array filter predicates >> selftests/ftrace: add test coverage for filter predicates >> tracing: document > 8 byte numeric filtering support >> >> Documentation/trace/events.rst | 9 +++ >> kernel/trace/trace_events_filter.c | 55 +++++++++++++++- >> .../selftests/ftrace/test.d/event/filter.tc | 62 +++++++++++++++++++ >> 3 files changed, 125 insertions(+), 1 deletion(-) >> create mode 100644 tools/testing/selftests/ftrace/test.d/event/filter.tc >> >> -- >> 2.31.1 >> > >
On Tue, 25 Apr 2023 18:15:03 +0100 Alan Maguire <alan.maguire@oracle.com> wrote: > that's a great idea; what would be the most consistent ftrace syntax > for this do you think? I noticed that hist triggers append a modifier > to the field name so would something like > > "dst.ipv6 == ::1" Yeah, I think just having ":" in the name without quotes can help the filter know that it's a ipv6 id. Hmm, although we may want to do the same for mac addresses. But we can determine the difference by the field size. If it's 6 bytes, it's a mac, if it's 128 bits, then ipv6. -- Steve
On 25/04/2023 18:20, Steven Rostedt wrote: > On Tue, 25 Apr 2023 18:15:03 +0100 > Alan Maguire <alan.maguire@oracle.com> wrote: > >> that's a great idea; what would be the most consistent ftrace syntax >> for this do you think? I noticed that hist triggers append a modifier >> to the field name so would something like >> >> "dst.ipv6 == ::1" > > Yeah, I think just having ":" in the name without quotes can help the filter > know that it's a ipv6 id. > > Hmm, although we may want to do the same for mac addresses. But we can > determine the difference by the field size. If it's 6 bytes, it's a mac, if > it's 128 bits, then ipv6. > good idea! so what about the following - 16 byte field with ':'; convert from IPv6 address before memcmp()ing - 6 byte field with ':'; convert from MAC address before memcmp()ing - 4 byte field with '.'; convert from IPv4 address before memcmp()ing - 0x prefix, any other size; basic memcmp ? Thanks! Alan > -- Steve >
On Wed, 26 Apr 2023 09:51:00 +0100 Alan Maguire <alan.maguire@oracle.com> wrote: > - 16 byte field with ':'; convert from IPv6 address before memcmp()ing > - 6 byte field with ':'; convert from MAC address before memcmp()ing > - 4 byte field with '.'; convert from IPv4 address before memcmp()ing > - 0x prefix, any other size; basic memcmp Sure. -- Steve
On Wed, 26 Apr 2023 09:51:00 +0100 Alan Maguire <alan.maguire@oracle.com> wrote: > On 25/04/2023 18:20, Steven Rostedt wrote: > > On Tue, 25 Apr 2023 18:15:03 +0100 > > Alan Maguire <alan.maguire@oracle.com> wrote: > > > >> that's a great idea; what would be the most consistent ftrace syntax > >> for this do you think? I noticed that hist triggers append a modifier > >> to the field name so would something like > >> > >> "dst.ipv6 == ::1" > > > > Yeah, I think just having ":" in the name without quotes can help the filter > > know that it's a ipv6 id. > > > > Hmm, although we may want to do the same for mac addresses. But we can > > determine the difference by the field size. If it's 6 bytes, it's a mac, if > > it's 128 bits, then ipv6. > > > > good idea! so what about the following > > - 16 byte field with ':'; convert from IPv6 address before memcmp()ing > - 6 byte field with ':'; convert from MAC address before memcmp()ing > - 4 byte field with '.'; convert from IPv4 address before memcmp()ing > - 0x prefix, any other size; basic memcmp This looks good to me :) Thanks! > > ? Thanks! > > Alan > > > -- Steve > >