perf: fix a number of corner-cases for small traces #168
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Upstream issue: brendangregg/FlameGraph#230 |
This was referenced Mar 29, 2020
jasonrhansen
previously approved these changes
Mar 31, 2020
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Upstream fix in brendangregg/FlameGraph#231 |
It turns out that sometimes, `perf script` spits out event lines that
_also_ include stack information, like so:
false 64414 20110.539243: 1893 cycles:u: 7fd5bd78f145 _dl_start+0x3c5 (/usr/lib/ld-2.31.so)
Which we would not handle correctly. This patch adds support for those
types of lines. I am not aware of anyone having run into this, but it
can happen if you do something like `perf record /bin/false`.
It turns out that upstream flamegraph does not do this, so we are now failing a lot of the upstream tests, which isn't great. I'll file an issue there, and we can wait to merge until that lands.
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This patch set includes three somewhat orthogonal fixes:
That last patch is a bit tricky, because upstream flamegraph does not do this, and so we now fail all of their perf collapse tests. I'll file an issue there and we can merge when that gets fixed upstream.