before this change, we rely on `using namespace seastar` to use
`seastar::format()` without qualifying the `format()` with its
namespace. this works fine until we changed the parameter type
of format string `seastar::format()` from `const char*` to
`fmt::format_string<...>`. this change practically invited
`seastar::format()` to the club of `std::format()` and `fmt::format()`,
where all members accept a templated parameter as its `fmt`
parameter. and `seastar::format()` is not the best candidate anymore.
despite that argument-dependent lookup (ADT for short) favors the
function which is in the same namespace as its parameter, but
`using namespace` makes `seastar::format()` more competitive,
so both `std::format()` and `seastar::format()` are considered
as the condidates.
that is what is happening scylladb in quite a few caller sites of
`format()`, hence ADT is not able to tell which function the winner
in the name lookup:
```
/__w/scylladb/scylladb/mutation/mutation_fragment_stream_validator.cc:265:12: error: call to 'format' is ambiguous
265 | return format("{} ({}.{} {})", _name_view, s.ks_name(), s.cf_name(), s.id());
| ^~~~~~
/usr/bin/../lib/gcc/x86_64-redhat-linux/14/../../../../include/c++/14/format:4290:5: note: candidate function [with _Args = <const std::basic_string_view<char> &, const seastar::basic_sstring<char, unsigned int, 15> &, const seastar::basic_sstring<char, unsigned int, 15> &, const utils::tagged_uuid<table_id_tag> &>]
4290 | format(format_string<_Args...> __fmt, _Args&&... __args)
| ^
/__w/scylladb/scylladb/seastar/include/seastar/core/print.hh:143:1: note: candidate function [with A = <const std::basic_string_view<char> &, const seastar::basic_sstring<char, unsigned int, 15> &, const seastar::basic_sstring<char, unsigned int, 15> &, const utils::tagged_uuid<table_id_tag> &>]
143 | format(fmt::format_string<A...> fmt, A&&... a) {
| ^
```
in this change, we
change all `format()` to either `fmt::format()` or `seastar::format()`
with following rules:
- if the caller expects an `sstring` or `std::string_view`, change to
`seastar::format()`
- if the caller expects an `std::string`, change to `fmt::format()`.
because, `sstring::operator std::basic_string` would incur a deep
copy.
we will need another change to enable scylladb to compile with the
latest seastar. namely, to pass the format string as a templated
parameter down to helper functions which format their parameters.
to miminize the scope of this change, let's include that change when
bumping up the seastar submodule. as that change will depend on
the seastar change.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
this change was created in the same spirit of ebff5f5d.
despite that we include Seastar as a submodule, Seastar is not a
part of scylla project. so we'd better include its headers using
brackets.
ebff5f5d addressed this cosmetic issue a while back. but probably
clangd's header-insertion helped some of contributor to insert
the missing headers with `"`. so this style of `include` returned
to the tree with these new changes.
unfortunately, clangd does not allow us to configure the style
of `include` at the time of writing.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#19406
before this change, we use `update_item_suffix` as a format string
fed to `format(...)`, which is resolved to `seastar::format()`.
but with a patch which migrates the `seastar::format()` to the backend
with compile-time format check, the caller sites using `format()` would
fail to build, because `update_item_suffix` is not a `constexpr`:
```
/home/kefu/.local/bin/clang++ -DFMT_SHARED -DSCYLLA_BUILD_MODE=release -DSEASTAR_API_LEVEL=7 -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SSTRING -DXXH_PRIVATE_API -DCMAKE_INTDIR=\"RelWithDebInfo\" -I/home/kefu/dev/scylladb -I/home/kefu/dev/scylladb/build/gen -I/home/kefu/dev/scylladb/seastar/include -I/home/kefu/dev/scylladb/build/seastar/gen/include -I/home/kefu/dev/scylladb/build/seastar/gen/src -isystem /home/kefu/dev/scylladb/abseil -isystem /home/kefu/dev/scylladb/build/rust -ffunction-sections -fdata-sections -O3 -g -gz -std=gnu++20 -fvisibility=hidden -Wall -Werror -Wextra -Wno-error=deprecated-declarations -Wimplicit-fallthrough -Wno-c++11-narrowing -Wno-deprecated-copy -Wno-mismatched-tags -Wno-missing-field-initializers -Wno-overloaded-virtual -Wno-unsupported-friend -Wno-enum-constexpr-conversion -Wno-unused-parameter -ffile-prefix-map=/home/kefu/dev/scylladb=. -march=westmere -mllvm -inline-threshold=2500 -fno-slp-vectorize -U_FORTIFY_SOURCE -Werror=unused-result -MD -MT test/perf/CMakeFiles/test-perf.dir/RelWithDebInfo/perf_alternator.cc.o -MF test/perf/CMakeFiles/test-perf.dir/RelWithDebInfo/perf_alternator.cc.o.d -o test/perf/CMakeFiles/test-perf.dir/RelWithDebInfo/perf_alternator.cc.o -c /home/kefu/dev/scylladb/test/perf/perf_alternator.cc
/home/kefu/dev/scylladb/test/perf/perf_alternator.cc:249:69: error: call to consteval function 'fmt::basic_format_string<char, const char (&)[1]>::basic_format_string<const char *, 0>' is not a constant expression
249 | return make_request(cli, "UpdateItem", prefix + seastar::format(update_item_suffix, ""));
| ^
/usr/include/fmt/core.h:2776:67: note: read of non-constexpr variable 'update_item_suffix' is not allowed in a constant expression
2776 | FMT_CONSTEVAL FMT_INLINE basic_format_string(const S& s) : str_(s) {
| ^
/home/kefu/dev/scylladb/test/perf/perf_alternator.cc:249:69: note: in call to 'basic_format_string<const char *, 0>(update_item_suffix)'
249 | return make_request(cli, "UpdateItem", prefix + seastar::format(update_item_suffix, ""));
| ^~~~~~~~~~~~~~~~~~
/home/kefu/dev/scylladb/test/perf/perf_alternator.cc:198:6: note: declared here
198 | auto update_item_suffix = R"(
| ^
```
so, to prepare the change switching to compile-time format checking,
let's mark this variable `static constexpr`. this is also more correct,
as this variable is
* a compile time constant, and
* is not shared across different compilation units.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18685
The code is based on similar idea as perf_simple_query. The main differences are:
- it starts full scylla process
- communicates with alternator via http (localhost)
- uses richer table schema with all dynamoDB types instead of only strings
Testing code runs in the same process as scylla so we can easily get various perf counters (tps, instr, allocation, etc).
Results on my machine (with 1 vCPU):
> ./build/release/scylla perf-alternator-workloads --workdir ~/tmp --smp 1 --developer-mode 1 --alternator-port 8000 --alternator-write-isolation forbid --workload read --duration 10 2> /dev/null
...
median 23402.59616090321
median absolute deviation: 598.77
maximum: 24014.41
minimum: 19990.34
> ./build/release/scylla perf-alternator-workloads --workdir ~/tmp --smp 1 --developer-mode 1 --alternator-port 8000 --alternator-write-isolation forbid --workload write --duration 10 2> /dev/null
...
median 16089.34211320635
median absolute deviation: 552.65
maximum: 16915.95
minimum: 14781.97
The above seem more realistic than results from perf_simple_query which are 96k and 49k tps (per core).
