Re: [systemd-devel] [PATCH v2 00/26] Initial DHCP v4 library implementation
On Mon, 09.12.13 23:41, Patrik Flykt (patrik.fl...@linux.intel.com) wrote: > > On Mon, 2013-11-25 at 23:52 +0100, Lennart Poettering wrote: > > Of course, timer callbacks should only be called once, ence > > ONESHOT mode is the default -- unless you change that explicitly. > > > > If this doesn't solve the issue, I wouldn't be surprised if there was > > still a bug lurking with the sd-event code. Note that I fixed a bug > > like this last week, did you check with currentl git of sd-event if > > the issue persists? > > Found the source of this issue. When the (monotonic) timeout function is > called with time 0 meaning "immediately", the callback indeed gets > called next by the event loop. But the uint64_t usec value passed to the > timer callback is the value 0 set by the caller, not the current > monotonic time the callback is called at. Yes, this is intended that way, so that for periodic usecases dispatch latencies don't add up. Of course, in your case having the actual time around is much more desirable. > Using the supplied usec value, > which is 0, as a base when calculating the next event timeout results of > course in a time very much smaller time than the current monotonic time, > causing the callback to be called immediately again. The value is again > the one set by the caller and thus the calculated time is again too low. > Rinse and repeat. > > I fixed the problem by using sd_event_get_now_monotonic() instead of the > supplied usec value as it wasn't clear what the intended behavior was. > systemd upstream version tested was from approximately last Friday > should something have changed recently. Yes, sd_event_get_now_monotonic() is the right call to use here. It will return the monotonic time of the current event loop iteration. Alternatively you could just use now(CLOCK_MONTONIC), but using sd_event_get_now_monotonic() helps to suppress a syscall... Lennart -- Lennart Poettering, Red Hat ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] [PATCH v2 00/26] Initial DHCP v4 library implementation
On Mon, 2013-11-25 at 23:52 +0100, Lennart Poettering wrote: > Of course, timer callbacks should only be called once, ence > ONESHOT mode is the default -- unless you change that explicitly. > > If this doesn't solve the issue, I wouldn't be surprised if there was > still a bug lurking with the sd-event code. Note that I fixed a bug > like this last week, did you check with currentl git of sd-event if > the issue persists? Found the source of this issue. When the (monotonic) timeout function is called with time 0 meaning "immediately", the callback indeed gets called next by the event loop. But the uint64_t usec value passed to the timer callback is the value 0 set by the caller, not the current monotonic time the callback is called at. Using the supplied usec value, which is 0, as a base when calculating the next event timeout results of course in a time very much smaller time than the current monotonic time, causing the callback to be called immediately again. The value is again the one set by the caller and thus the calculated time is again too low. Rinse and repeat. I fixed the problem by using sd_event_get_now_monotonic() instead of the supplied usec value as it wasn't clear what the intended behavior was. systemd upstream version tested was from approximately last Friday should something have changed recently. Cheers, Patrik ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] [PATCH v2 00/26] Initial DHCP v4 library implementation
Hi, On Mon, 2013-11-25 at 23:52 +0100, Lennart Poettering wrote: > Of course, timer callbacks should only be called once, ence ONESHOT > mode is the default -- unless you change that explicitly. Event loop code said ONESHOT for timers, and I don't think I managed to change that. > If this doesn't solve the issue, I wouldn't be surprised if there was > still a bug lurking with the sd-event code. Note that I fixed a bug > like this last week, did you check with currentl git of sd-event if > the issue persists? I did the testing with the code from the beginning of last week, then rebased on top of the latest so the bug may have disappeared already. I'll take another look. Cheers, Patrik ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] [PATCH v2 00/26] Initial DHCP v4 library implementation
On Mon, 25.11.13 09:13, Patrik Flykt (patrik.fl...@linux.intel.com) wrote: > After that I noticed someting interesting when setting a monotonic timer > event to go off at time 0. It seems to repeatedly call the timer event > without stopping, either due to the next timer computation going wrong in > my code or then the reshuffling of the event queue in sd-event. As I > couldn't figure out the root cause, I left the timer setting to > now(CLOCK_MONOTONIC) instead of the proposed value 0. Hmm, are you aware of SD_EVENT_SOURCE_ON vs. SD_EVENT_SOURCE_ONESHOT? The former leaves the event source on forever, and that means a timer is dispatched over and over and over again (immediately, since the rule is to execute a timer as soon as the configured time is passed, and that it will be continously after it elapsed once), until it is explicitly disabled. The latter is turned off automatically when it is first dispatched. Of course, timer callbacks should only be called once, ence ONESHOT mode is the default -- unless you change that explicitly. If this doesn't solve the issue, I wouldn't be surprised if there was still a bug lurking with the sd-event code. Note that I fixed a bug like this last week, did you check with currentl git of sd-event if the issue persists? Lennart -- Lennart Poettering, Red Hat ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] [PATCH v2 00/26] Initial DHCP v4 library implementation
Hi, Here is version 2 of the libsystemd-dhcp patch set fixed according to comments. Functionality is the same as in the earlier version. I'm still usin src/dhcp as the location for this code, but what might be the proper directory for the code eventually? I also left it conditionally enabled by default, should it be compiled unconditionally in the future? I chose to drop the example DHCP client, it seems systemd-network is right around the corner so yet another piece of code doing something very similar is probably not very worthwhile. Thus the set shrunk with two patches. In addition to this, I added struct sockaddr_ll to sockaddr_union in patch 11/26. It wasn't possible to use _cleanup_free_ while handling the DHCP lease structure as freeing the structure afterwards is only to be done on error conditions. DHCP_EVENT_NAK was renamed to the hopefully more useful DHCP_EVENT_NO_LEASE and the public API is now in src/systemd/sd-dhcp-client.h. I also created a function for fetching the prefix length instead of netmask. After that I noticed someting interesting when setting a monotonic timer event to go off at time 0. It seems to repeatedly call the timer event without stopping, either due to the next timer computation going wrong in my code or then the reshuffling of the event queue in sd-event. As I couldn't figure out the root cause, I left the timer setting to now(CLOCK_MONOTONIC) instead of the proposed value 0. Please review, Patrik Patrik Flykt (26): dhcp: Add DHCP protocol structures and initial defines dhcp: Add DHCP client initialization dhcp: Add test for DHCP client initialization and parameter setting build: Add initial build support dhcp: Add option appending and parsing dhcp: Add buffer length and invalid cookie tests for DHCP options build: Add DHCP option test dhcp: Add tests for DHCP options, file and sname fields dhcp: Add option append tests dhcp: Add test function for computing checksum shared: Add struct sockaddr_ll to sockaddr_union dhcp: Add function for sending a raw packet dhcp: Add DHCP discover sending build: Add libsystemd-dhcp dhcp: Add test for discover DHCP packet creation dhcp: Support seconds elapsed since start of DHCP negotiation dhcp: Add function to stop the DHCP client build: Add dependency on libsystemd-bus needed for main loop dhcp: Add timeout and main loop support dhcp: Handle received DHCP Offer message dhcp: Send DHCP Request to acquire an IP address dhcp: Add maximum message size option dhcp: Process DHCP Ack/Nak message dhcp: Compute expire, T1 and T2 timers dhcp: Add notification callback dhcp: Add function to free DHCP client data Makefile.am | 50 +++ configure.ac |9 + src/dhcp/Makefile|1 + src/dhcp/client.c| 981 ++ src/dhcp/internal.h | 41 ++ src/dhcp/network.c | 64 +++ src/dhcp/option.c| 181 src/dhcp/protocol.h | 119 + src/dhcp/test-dhcp-client.c | 224 ++ src/dhcp/test-dhcp-option.c | 376 src/shared/socket-util.h |2 + src/systemd/sd-dhcp-client.h | 57 +++ 12 files changed, 2105 insertions(+) create mode 12 src/dhcp/Makefile create mode 100644 src/dhcp/client.c create mode 100644 src/dhcp/internal.h create mode 100644 src/dhcp/network.c create mode 100644 src/dhcp/option.c create mode 100644 src/dhcp/protocol.h create mode 100644 src/dhcp/test-dhcp-client.c create mode 100644 src/dhcp/test-dhcp-option.c create mode 100644 src/systemd/sd-dhcp-client.h -- 1.7.10.4 ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
