Thanks. I will follow up with Francesco and Sebastiano.
Pablo
On 2/22/18 1:58 AM, Fulvio Risso wrote:
Pablo,
this looks very similar to Francesco's request here:
https://lists.iovisor.org/pipermail/iovisor-dev/2018-February/001225.html
FYI, Francesco and Sebastiano are currently working on a patch to
enable this feature. You can get in touch directly with them.
fulvio
On 21/02/2018 17:49, Alvarez, Pablo via iovisor-dev wrote:
Dear devs,
Is there a way to poll() or select() or otherwise not-busy-wait on a
bpf map in userspace? I would like to react quickly to new data
coming into the map from my bpf program withoug consuming too many
resources.
I ran an experiment using the map fd and poll(), and found that the
revents field always returned with POLLIN set, whether there was new
data in the map or not. This makes a certain sense, since one never
calls read() on the map to clear the field, but is not particularly
useful.
The question applies both to
- a tc cls map added with "tc filter add dev eth0 egress bpf da obj
clsact_get_packet.o sec getpacket"
- a map accessed from a bpf program inserted into a TCP socket (with
load_bpf_file() and setsockopt(sockfd, SOL_SOCKET, SO_ATTACH_BPF,
prog_fd, sizeof(prog_fd[0])).
If not, is there another way to get a bpf program to signal up to
userspace that something has happened?
Thanks
Pablo Alvarez
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