Re: [PATCH V4 07/22] LoongArch: Add atomic/locking headers

[Huacai Chen]

Hi, Peter,

On Fri, Oct 1, 2021 at 7:04 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Mon, Sep 27, 2021 at 02:42:44PM +0800, Huacai Chen wrote:
> > diff --git a/arch/loongarch/include/asm/spinlock.h b/arch/loongarch/include/asm/spinlock.h
> > new file mode 100644
> > index 000000000000..2544ee546596
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/spinlock.h
> > @@ -0,0 +1,12 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +#ifndef _ASM_SPINLOCK_H
> > +#define _ASM_SPINLOCK_H
> > +
> > +#include <asm/processor.h>
> > +#include <asm/qspinlock.h>
> > +#include <asm/qrwlock.h>
> > +
> > +#endif /* _ASM_SPINLOCK_H */
> > diff --git a/arch/loongarch/include/asm/spinlock_types.h b/arch/loongarch/include/asm/spinlock_types.h
> > new file mode 100644
> > index 000000000000..91f258401ef9
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/spinlock_types.h
> > @@ -0,0 +1,11 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +#ifndef _ASM_SPINLOCK_TYPES_H
> > +#define _ASM_SPINLOCK_TYPES_H
> > +
> > +#include <asm-generic/qspinlock_types.h>
> > +#include <asm-generic/qrwlock_types.h>
> > +
> > +#endif
>
> Also see the many lkml threads on this, is there big enough loongson to
> justify qspinlock? Have you tried a ticket lock?
Loongson-3A5000 supports NUMA, we have as many as 16 nodes, 64 cores
in total. And we have tried ticket lock which is worse than qspinlock.
Maybe Jun Yi (yili0568@xxxxxxxxx) can give some performace data?

Huacai