[lttng-dev] Add support for the LOONGARCH architecture

[Mathieu Desnoyers]

Hi,

I notice that the loongarch enablement patch defines:

#define UATOMIC_HAS_ATOMIC_BYTE
#define UATOMIC_HAS_ATOMIC_SHORT

I tried looking into

  https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#atomic-memory-access-instructions

to figure out which atomic instructions or LL/SC would be used to target 1 and 2 byte
variables atomically, but could only find instructions for word and double-word:

2.2.7.1. AM{SWAP/ADD/AND/OR/XOR/MAX/MIN}[DB].{W/D}, AM{MAX/MIN}[_DB].{WU/DU}
2.2.7.2. LL.{W/D}, SC.{W/D}

What am I missing here ?

Thanks,

Mathieu

----- On Jan 24, 2022, at 6:59 AM, lttng-dev lttng-dev at lists.lttng.org wrote:

> Unfortunately, the qemu approach does not help much in testing that the
> liburcu implementation works correctly on a given architecture's
> specific memory model.
> 
> liburcu relies heavily on memory ordering, and liburcu-cds relies on
> both memory ordering and atomic operations and the memory ordering
> guarantees associated with them.
> 
> So if there is any way we could get our hands on real hardware, it
> would be very much relevant for liburcu testing.
> 
> Thanks,
> 
> Mathieu
> 
> ----- On Jan 24, 2022, at 3:02 AM, 张文龙 zhangwenlong at loongson.cn wrote:
> 
>> I'm glad the new architecture can be accepted，At present, our machines are in
>> short supply.I need to go through a very complicated process to provide
>> machines, Can qemu emulator work?
>> 
>> 
>> > -----原始邮件-----
>> > 发件人: "Mathieu Desnoyers" <mathieu.desnoyers at efficios.com>
>> > 发送时间: 2022-01-20 23:59:52 (星期四)
>> > 收件人: "张文龙" <zhangwenlong at loongson.cn>
>> > 抄送: lttng-dev <lttng-dev at lists.lttng.org>
>> > 主题: Re: [lttng-dev] Add support for the LOONGARCH architecture
>> >
>> > ----- On Jan 19, 2022, at 11:03 PM, lttng-dev lttng-dev at lists.lttng.org
>> wrote:
>> >
>> > > Hello, I'm excited to contribute to userspace-rcu, I added loongarch
>> > > architecture for userspace-rcu（ The patch file is
>> > > 0001-Add-support-for-the-LOONGARCH-architecture.patch )
>> >
>> > > I have compiled and verified locally (the build log is build_log.txt
>> ),and then
>> > > i runed make check（ the make check log is make_check_log.txt ）， make
>> > > regtest（the make regtest log is make_regtest_log.txt ） ， make
>> short_bench (the
>> > > make short_bench log is make_short_bench_log.txt ),make long_bench(the
>> make
>> > > long_bench log is make_long_bench_log.txt )
>> >
>> > This is great, thanks !
>> >
>> > By the way, is there any way EfficiOS could add two loongarch test boards
>> into
>> > our test rack for automated CI testing ? See https://ci.lttng.org
>> >
>> > We typically deploy at least two boards for each given architecture for
>> redundancy
>> > and availability for both CI and development use.
>> >
>> > This would help ensuring we catch liburcu regressions in the loongarch
>> architecture
>> > in the future.
>> >
>> > Thanks,
>> >
>> > Mathieu
>> >
>> >
>> > > 本邮件及其附件含有龙芯中科的商业秘密信息，仅限于发送给上面地址中列出的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或部
>> > > 分地泄露、复制或散发）本邮件及其附件中的信息。如果您错收本邮件，请您立即电话或邮件通知发件人并删除本邮件。
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>> > --
>> > Mathieu Desnoyers
>> > EfficiOS Inc.
>> > http://www.efficios.com
>> </lttng-dev at lists.lttng.org></zhangwenlong at loongson.cn></mathieu.desnoyers at efficios.com>
>> 
>> 本邮件及其附件含有龙芯中科的商业秘密信息，仅限于发送给上面地址中列出的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制或散发）本邮件及其附件中的信息。如果您错收本邮件，请您立即电话或邮件通知发件人并删除本邮件。
>> This email and its attachments contain confidential information from Loongson
>> Technology , which is intended only for the person or entity whose address is
>> listed above. Any use of the information contained herein in any way
>> (including, but not limited to, total or partial disclosure, reproduction or
>> dissemination) by persons other than the intended recipient(s) is prohibited.
>> If you receive this email in error, please notify the sender by phone or email
>> immediately and delete it.
> 
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> http://www.efficios.com
> _______________________________________________
> lttng-dev mailing list
> lttng-dev at lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com