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author | Arnd Bergmann <[email protected]> | 2018-07-09 10:34:43 +0200 |
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committer | Jason Gunthorpe <[email protected]> | 2018-07-11 12:10:19 -0600 |
commit | 07f3355df7e6d043d36d4c172a18e74510fe7e7b (patch) | |
tree | af9dd5aec8f33edaa2c88caa964d136f513ffc83 /tools/perf/util/scripting-engines/trace-event-python.c | |
parent | 59b851dbf7dc94214e4fab5dd29ea28b4075a04f (diff) |
infiniband: i40iw, nes: don't use wall time for TCP sequence numbers
The nes infiniband driver uses current_kernel_time() to get a nanosecond
granunarity timestamp to initialize its tcp sequence counters. This is
one of only a few remaining users of that deprecated function, so we
should try to get rid of it.
Aside from using a deprecated API, there are several problems I see here:
- Using a CLOCK_REALTIME based time source makes it predictable in
case the time base is synchronized.
- Using a coarse timestamp means it only gets updated once per jiffie,
making it even more predictable in order to avoid having to access
the hardware clock source
- The upper 2 bits are always zero because the nanoseconds are at most
999999999.
For the Linux TCP implementation, we use secure_tcp_seq(), which appears
to be appropriate here as well, and solves all the above problems.
i40iw uses a variant of the same code, so I do that same thing there
for ipv4. Unlike nes, i40e also supports ipv6, which needs to call
secure_tcpv6_seq instead.
Acked-by: Shiraz Saleem <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Diffstat (limited to 'tools/perf/util/scripting-engines/trace-event-python.c')
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