On 6/17/20 2:44 AM, Martin Liška wrote:
Hello.
As mentioned in the PR, gcda files tend to occupy a large disk space
when each running process streams to its own directory. The test-case
in the PR has very low coverage and so that the data file contain
a lot of zero records.
The patch is attempt to not stream these zero COUNTERS:
a-tramp3d-v4.gcda: 01a10000: 38:COUNTERS arcs 19 counts (all zero)
a-tramp3d-v4.gcda: 0: 0 0 0 0 0 0 0 0
a-tramp3d-v4.gcda: 8: 0 0 0 0 0 0 0 0
a-tramp3d-v4.gcda: 16: 0 0 0
Here we stream -19 as count and any of the 0 is streamed.
neat
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
The patch survives PGO bootstrap of GCC and it shrinks size of gcda
file from 17MB to 12MB.
One alternative approach could be to use a normal compression (zlib, zstd)
for output file? That can save even more space.
What's the size of zlib (or other) compression of that 17MB file?
nathan
--
Nathan Sidwell
