[zig cc] 3x+ slower ./configure times with zig cc, compared to clang/gcc #24318
Description
Zig Version
0.15-dev
Steps to Reproduce and Observed Behavior
Let me preface this by saying that I'm not entirely sure whether it is a bug, or a side effect of zig having to check for libc symbols every time anew. Maybe there is a way to first dump a precompiled sysroot for it and use that, to speed it up? I couldn't find any such information, unfortunately.
Preparation:
wget https://pkgconfig.freedesktop.org/releases/pkg-config-0.29.tar.gz
tar -xzf pkg-config-0.29.tar.gz
cd pkg-config-0.29/
Time clang:
CC=clang /usr/bin/time -v ./configure --with-internal-glib --disable-host-tool --without-sysroot --without-system-include-path --without-system-library-path --without-pc-path --disable-shared --enable-static --prefix=/home/m/static-php-cli/buildroot --with-pic
->
User time (seconds): 4.15
System time (seconds): 1.88
Percent of CPU this job got: 38%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:15.75
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 82500
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 4
Minor (reclaiming a frame) page faults: 3244215
Voluntary context switches: 105361
Involuntary context switches: 98
Swaps: 0
File system inputs: 176
File system outputs: 20904
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0
Time zig cc:
CC="zig cc" /usr/bin/time -v ./configure --with-internal-glib --disable-host-tool --without-sysroot --without-system-include-path --without-system-library-path --without-pc-path --disable-shared --enable-static --prefix=/home/m/static-php-cli/buildroot --with-pic
->
User time (seconds): 7.44
System time (seconds): 3.32
Percent of CPU this job got: 20%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:52.72
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 67312
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 403
Minor (reclaiming a frame) page faults: 4484282
Voluntary context switches: 672005
Involuntary context switches: 425
Swaps: 0
File system inputs: 6048
File system outputs: 21584
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0
Expected Behavior
Identical logs and nearly identical times.
The logs are nearly identical, with the only difference being:
-checking for growing stack pointer... yes
+checking for growing stack pointer... no`But the times are wildly different:
-User time (seconds): 4.15
-System time (seconds): 1.88
-Percent of CPU this job got: 38%
-Elapsed (wall clock) time (h:mm:ss or m:ss): 0:15.75
+User time (seconds): 7.44
+System time (seconds): 3.32
+Percent of CPU this job got: 20%
+Elapsed (wall clock) time (h:mm:ss or m:ss): 0:52.72The percent of CPU this job got varies from 20-40% on both sides, but the times don't change in a meaningful way.