Re: Any known way to build devel/llvm* ( such as devel/llvm19 ) with --threads=1 for its linker activity during the build?

On Aug 4, 2024, at 22:53, Michal Meloun <meloun.michal@gmail.com> wrote:

> On 04.08.2024 23:31, Mark Millard wrote:
>> On Aug 3, 2024, at 23:07, Mark Millard <marklmi@yahoo.com> wrote:
>>> My recent attempts to build devel/llvm18 and devel/llvm19 in an armv7 context (native or aarch64-as-armv7) have had /usr/bin/ld failures that stop the build and report as:
>>> 
>>> LLVM ERROR: out of memory
>>> Allocation failed
>>> 
>>> (no system OOM activity or notices, so just a process size/fragmentation issue, or so I would expect).
>>> 
>>> On native armv7 I also had rust 1.79.0 fail that way so --but aarch64-as-armv7 built it okay.
>>> 
>>> I'm curious if --threads=1 use for the linker might allow the devel/llvm* builds to complete at this point. Similarly for rust. (top showed that the ld activity was multi-threaded.)
>>> 
>>> Note: The structure of the poudriere-devel based native build attempts is historical and it used to work. Similarly for the aarch64-as-armv7 based build attempts. For now I'd just be exploring changes that might allow much of my historical overall structure to still work. But I expect that things are just growing to the point building is starting to be problematical with process address spaces that are bounded by a limit somewhat under 4 GiBytes.
>>> 
>>> 
>>> Native armv7 was a 2 GiByte OrangePi+ 2ed (4 cores) that had
>>> at boot time:
>>> 
>>> AVAIL_RAM+SWAP == 1958Mi+3685Mi == 5643Mi
>>> 
>>> and later had "Max(imum)Obs(erved)" figures:
>>> 
>>> Mem: . . .,
>>> 1728Mi MaxObsActive, 275192Ki MaxObsWired, 1952Mi MaxObs(Act+Wir+Lndry)
>>> 
>>> Swap: 3685Mi Total, . . .,
>>> 1535Mi MaxObsUsed, 3177Mi MaxObs(Act+Lndry+SwapUsed),
>>> 3398Mi MaxObs(A+Wir+L+SU), 3449Mi (A+W+L+SU+InAct)
>>> 
>>> 
>>> The aarch64-as-armv7 was a Win DevKit 2023 that has 8 cores and:
>>> 
>>> AVAIL_RAM+SWAP == 31311Mi+120831Mi == 152142Mi
>>> 
>>> So lots of 4 GiByte or smaller processes would fit.
>>> 
>> Absent finding a way to get --threads=1 to be what is used, I
>> made the following crude way to test, built it, installed it
>> in the armv7 directory tree used for aarch64-as-armv7, and
>> then started an aarch64-as-armv7 test of building devel/llvm19
>> to see what the consequences are (leading whitespace details
>> might not be preserved):
>> # git -C /usr/main-src/ diff contrib/llvm-project/
>> diff --git a/contrib/llvm-project/lld/ELF/Driver.cpp b/contrib/llvm-project/lld/ELF/Driver.cpp
>> index 8b2c32b15348..299daf7dd6fa 100644
>> --- a/contrib/llvm-project/lld/ELF/Driver.cpp
>> +++ b/contrib/llvm-project/lld/ELF/Driver.cpp
>> @@ -1587,6 +1587,9 @@ static void readConfigs(opt::InputArgList &args) {
>>              arg->getValue() + "'");
>>      parallel::strategy = hardware_concurrency(threads);
>>      config->thinLTOJobs = v;
>> +  } else if (sizeof(void*) <= 4) {
>> +    log("set maximum concurrency to 1, specify --threads= to change");
>> +    parallel::strategy = hardware_concurrency(1);
>>    } else if (parallel::strategy.compute_thread_count() > 16) {
>>      log("set maximum concurrency to 16, specify --threads= to change");
>>      parallel::strategy = hardware_concurrency(16);
>> Basically, if the process address space has to be "small", avoid
>> any default memory use tradeoffs that multi-threading the linker
>> might involve --even if that means taking more time.
>> We will see if:
>> [00:00:33] [07] [00:00:00] Building   devel/llvm19@default | llvm19-19.1.0.r1
>> still fails to build as armv7 vs. if the change leads it to
>> manage to build as armv7.
>> ===
>> Mark Millard
>> marklmi at yahoo.com
> 
> I can build llvm18 and rust 1.79 on native armv7  without problems - on Tegra TK1, without poudriere and on the ufs filesystem. IMHO poudriere is unusable on 32bit systems.

On Windows DevKit 2023 in a armv7 chroot I can build rust 1.79.0
as well. I've not tried a recent devel/llvm18 in that context,
just devel/llvm19 . An armv7 process in this context can use
about 1 GiByte more memory space than on the OrangePi+ 2ed. (See
later program example outputs.)

Previously, devel/llvm18-18.1.7 had built fine some time back.
So I'm trying the modern 18.1.8_1 now on the Windows DevKit 2023.
But this is with forcing of --threads=1 for lld: same context as
the recent devel/llvm19 exploration.

Note: UFS context, not ZFS.

How does the Tegra TK1 context compare for the following
program and the example command?

OrangePi+ 2ed (so: armv7 native with 2 GiBytes of RAM):

# more process_size.c
// cc -std=c11 process_size.c
// ./a.out 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 134217728 67108864 33554432 16777216 8388608 4194304 2097152 1048576

#include <malloc.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

int main(int argc, char *argv[])
{
 size_t totalsize= 0u;
 for (int i = 1; i < argc; ++i) {
   errno = 0;
   size_t size = strtoul(argv[i],NULL,0);
   void *p = malloc(size);
   if (p) totalsize += size;
   printf("malloc(%zu) = %p [errno = %d]\n", size, p, errno);
 }
 printf("approx. total, a lower bound: %zu MiBytes\n", totalsize/1024u/1024u);
 return 0;
}
# cc -std=c11 process_size.c
# ./a.out 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 134217728 67108864 33554432 16777216 8388608 4194304 2097152 1048576
malloc(268435456) = 0x20800180 [errno = 0]
malloc(268435456) = 0x30801980 [errno = 0]
malloc(268435456) = 0x40802640 [errno = 0]
malloc(268435456) = 0x50803600 [errno = 0]
malloc(268435456) = 0x608048c0 [errno = 0]
malloc(268435456) = 0x70805140 [errno = 0]
malloc(268435456) = 0x80806580 [errno = 0]
malloc(268435456) = 0x90807780 [errno = 0]
malloc(268435456) = 0xa0808700 [errno = 0]
malloc(268435456) = 0x0 [errno = 12]
malloc(268435456) = 0x0 [errno = 12]
malloc(268435456) = 0x0 [errno = 12]
malloc(268435456) = 0x0 [errno = 12]
malloc(134217728) = 0xb0809a00 [errno = 0]
malloc(67108864) = 0x0 [errno = 12]
malloc(33554432) = 0xb880a5c0 [errno = 0]
malloc(16777216) = 0xba80b0c0 [errno = 0]
malloc(8388608) = 0x0 [errno = 12]
malloc(4194304) = 0x0 [errno = 12]
malloc(2097152) = 0xbb80c180 [errno = 0]
malloc(1048576) = 0xbba0de80 [errno = 0]
approx. total, a lower bound: 2483 MiBytes


Same program with same command on Windows DevKit 2023 in
armv7 chroot (aarch64-as-armv7 with 32 GiBytes of RAM):

# ./a.out 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 268435456 134217728 67108864 33554432 16777216 8388608 4194304 2097152 1048576
malloc(268435456) = 0x20800b00 [errno = 0]
malloc(268435456) = 0x30801600 [errno = 0]
malloc(268435456) = 0x40802cc0 [errno = 0]
malloc(268435456) = 0x50803c80 [errno = 0]
malloc(268435456) = 0x608042c0 [errno = 0]
malloc(268435456) = 0x70805b00 [errno = 0]
malloc(268435456) = 0x808063c0 [errno = 0]
malloc(268435456) = 0x90807580 [errno = 0]
malloc(268435456) = 0xa0808b40 [errno = 0]
malloc(268435456) = 0xb0809980 [errno = 0]
malloc(268435456) = 0xc080abc0 [errno = 0]
malloc(268435456) = 0xd080ba00 [errno = 0]
malloc(268435456) = 0xe080cc80 [errno = 0]
malloc(134217728) = 0xf080d700 [errno = 0]
malloc(67108864) = 0x0 [errno = 12]
malloc(33554432) = 0xf880eb40 [errno = 0]
malloc(16777216) = 0xfa80fc00 [errno = 0]
malloc(8388608) = 0x0 [errno = 12]
malloc(4194304) = 0xfb810840 [errno = 0]
malloc(2097152) = 0xfbc117c0 [errno = 0]
malloc(1048576) = 0xfbe12940 [errno = 0]
approx. total, a lower bound: 3511 MiBytes


Note: If the Tegra TK1 in question has more than
4 GiBytes  of RAM, the command line should explore
more than the example that I used.


Note: I've used the program for other patterns of
allocations. That is why it is not just a fixed
exploration algorithm.


As for poudriere-devel, I find it useful, even on
the OrangePi+ 2ed. But mostly that is a rare run
that is checking on how well the handling goes for
the 2 GiByte of RAM context (with notable SWAP for
the size of RAM). In other words, monitoring the
growth in a context that will break sooner than
my other contexts generally would. The tests take
days overall, most of the time being for rust and
a llvm* .

Historically I've been able to have 2 builders,
each with MAKE_JOBS_NUMBER_LIMIT=2 , so all 4
cores in use building lang/rust and a devel/llvm*
at the same time successfully in poudriere-devel
on the 2 GiByte OrangePi+ 2ed. (This was before
recently imposing --threads=1 experiments,
given the recent build failures.)

===
Mark Millard
marklmi at yahoo.com