From: "Jose E. Marchesi" <jose.marchesi@oracle.com>
To: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>,
bpf@vger.kernel.org, Yonghong Song <yhs@meta.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
david.faust@oracle.com, cupertino.miranda@oracle.com
Subject: Re: [PATCH bpf-next] bpf: abstract loop unrolling pragmas in BPF selftests
Date: Thu, 08 Feb 2024 16:05:00 +0100 [thread overview]
Message-ID: <87o7crdmjn.fsf@oracle.com> (raw)
In-Reply-To: <4ad9dad64b38ae90e4a050ce5181ced750913b23.camel@gmail.com> (Eduard Zingerman's message of "Thu, 08 Feb 2024 16:18:55 +0200")
> On Thu, 2024-02-08 at 13:55 +0100, Jose E. Marchesi wrote:
> [...]
>
>> However, it would be good if some clang wizard could confirm what
>> impact, if any, #pragma unroll (aka #pragma clang loop unroll(enabled))
>> has over -O2, before ditching these pragmas from the selftests.
>
> I compiled sefltests both with and without this patch,
> there are no differences in disassembly of generated BPF object files.
> (using current clang main).
>
> [...]
Hmm, wouldn't that mean that the loops in profiler.inc.h never get
unrolled regardless of optimization level or pragma? (profiler2.c)
next prev parent reply other threads:[~2024-02-08 15:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-07 10:12 [PATCH bpf-next] bpf: abstract loop unrolling pragmas in BPF selftests Jose E. Marchesi
2024-02-07 21:45 ` Yonghong Song
2024-02-08 11:32 ` Jose E. Marchesi
2024-02-08 12:55 ` Jose E. Marchesi
2024-02-08 14:18 ` Eduard Zingerman
2024-02-08 15:05 ` Jose E. Marchesi [this message]
2024-02-08 15:28 ` Eduard Zingerman
2024-02-08 15:35 ` Jose E. Marchesi
2024-02-08 15:53 ` Eduard Zingerman
2024-02-08 16:51 ` Jose E. Marchesi
2024-02-08 18:04 ` Yonghong Song
2024-02-08 18:35 ` Yonghong Song
2024-02-08 18:59 ` Jose E. Marchesi
2024-02-08 19:03 ` Jose E. Marchesi
2024-02-08 19:34 ` Eduard Zingerman
2024-02-08 19:44 ` Yonghong Song
2024-02-08 19:49 ` Yonghong Song
2024-02-08 20:06 ` Jose E. Marchesi
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