Load-balancing update_verifier worker threads.
Prior to this CL, the block verification works were assigned based on
the pattern of the ranges, which could lead to unbalanced workloads. This
CL adds RangeSet::Split() and moves update_verifier over.
a) For the following care_map.txt on walleye:
system
20,0,347,348,540,556,32770,33084,98306,98620,163842,164156,229378,229692,294914,295228,524289,524291,524292,524348,529059
vendor
8,0,120,135,32770,32831,94564,98304,98306
Measured the time costs prior to and with this CL with the following
script.
$ cat test_update_verifier.sh
#!/bin/sh
adb shell stop
adb shell "cp /data/local/tmp/care_map.txt /data/ota_package/"
for i in $(seq 1 50)
do
echo "Iteration: $i"
adb shell "bootctl set-active-boot-slot 0"
adb shell "echo 3 > /proc/sys/vm/drop_caches"
adb shell "time /data/local/tmp/update_verifier"
sleep 3
done
Without this CL, the average time cost is 5.66s, while with the CL it's
reduced to 3.2s.
b) For the following care_map.txt, measured the performance on marlin:
system
18,0,271,286,457,8350,32770,33022,98306,98558,163842,164094,196609,204800,229378,229630,294914,295166,501547
vendor
10,0,42,44,85,2408,32770,32806,32807,36902,74242
It takes 12.9s and 5.6s without and with the CL respectively.
Fixes: 68553827
Test: recovery_unit_test
Test: Flash new build and trigger update_verifier. Check the balanced
block verification.
Change-Id: I5fa4bf09a84e6b9b0975ee5f522724464181333f
diff --git a/otautil/rangeset.cpp b/otautil/rangeset.cpp
index 532cba4..96955b9 100644
--- a/otautil/rangeset.cpp
+++ b/otautil/rangeset.cpp
@@ -103,6 +103,46 @@
blocks_ = 0;
}
+std::vector<RangeSet> RangeSet::Split(size_t groups) const {
+ if (ranges_.empty() || groups == 0) return {};
+
+ if (blocks_ < groups) {
+ groups = blocks_;
+ }
+
+ // Evenly distribute blocks, with the first few groups possibly containing one more.
+ size_t mean = blocks_ / groups;
+ std::vector<size_t> blocks_per_group(groups, mean);
+ std::fill_n(blocks_per_group.begin(), blocks_ % groups, mean + 1);
+
+ std::vector<RangeSet> result;
+
+ // Forward iterate Ranges and fill up each group with the desired number of blocks.
+ auto it = ranges_.cbegin();
+ Range range = *it;
+ for (const auto& blocks : blocks_per_group) {
+ RangeSet buffer;
+ size_t needed = blocks;
+ while (needed > 0) {
+ size_t range_blocks = range.second - range.first;
+ if (range_blocks > needed) {
+ // Split the current range and don't advance the iterator.
+ buffer.PushBack({ range.first, range.first + needed });
+ range.first = range.first + needed;
+ break;
+ }
+ buffer.PushBack(range);
+ it++;
+ if (it != ranges_.cend()) {
+ range = *it;
+ }
+ needed -= range_blocks;
+ }
+ result.push_back(std::move(buffer));
+ }
+ return result;
+}
+
std::string RangeSet::ToString() const {
if (ranges_.empty()) {
return "";