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Re: [Qemu-devel] [PATCH 03/22] cputlb: bring back tlb_flush_count under
From: |
Emilio G. Cota |
Subject: |
Re: [Qemu-devel] [PATCH 03/22] cputlb: bring back tlb_flush_count under !TLB_DEBUG |
Date: |
Wed, 12 Jul 2017 14:19:45 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Wed, Jul 12, 2017 at 14:26:36 +0100, Alex Bennée wrote:
> Emilio G. Cota <address@hidden> writes:
(snip)
> > This patch does the latter by embedding tlb_flush_count in CPUArchState.
> > The global count is then easily obtained by iterating over the CPU list.
> >
> > Signed-off-by: Emilio G. Cota <address@hidden>
>
> As it actually fixes unintentional breakage:
>
> Reviewed-by: Alex Bennée <address@hidden>
>
> That said I'm not sure if this number alone is helpful given the range
> of flushes we have. Really from a performance point of view we should
> differentiate between inline per-vCPU flushes as well as the cross-vCPU
> flushes of both asynchronus and synced varieties.
>
> I had a go at this using QEMUs tracing infrastructure:
>
> https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg04076.html
>
> But I guess the ideal way would be something that both keeps counters
> and optionally enable tracepoints.
Yeah the counters in my patch are there to fix the breakage while
not hurting scalability in MTTCG.
Having those counters always on + the tracers in your patchset
for more detailed info seems reasonable to me.
Maybe it's time to push to get those tracers changes in?
Emilio
- [Qemu-devel] [PATCH 13/22] tcg: take tb_ctx out of TCGContext, (continued)
- [Qemu-devel] [PATCH 13/22] tcg: take tb_ctx out of TCGContext, Emilio G. Cota, 2017/07/09
- [Qemu-devel] [PATCH 10/22] exec-all: move tb->invalid to the end of the struct, Emilio G. Cota, 2017/07/09
- [Qemu-devel] [PATCH 20/22] tcg: dynamically allocate from code_gen_buffer using equally-sized regions, Emilio G. Cota, 2017/07/09
- [Qemu-devel] [PATCH 03/22] cputlb: bring back tlb_flush_count under !TLB_DEBUG, Emilio G. Cota, 2017/07/09
- Re: [Qemu-devel] [PATCH 03/22] cputlb: bring back tlb_flush_count under !TLB_DEBUG, Alex Bennée, 2017/07/12
- Re: [Qemu-devel] [PATCH 03/22] cputlb: bring back tlb_flush_count under !TLB_DEBUG,
Emilio G. Cota <=
- [Qemu-devel] [PATCH 15/22] gen-icount: fold exitreq_label into TCGContext, Emilio G. Cota, 2017/07/09
- [Qemu-devel] [PATCH 05/22] exec-all: fix typos in TranslationBlock's documentation, Emilio G. Cota, 2017/07/09
- [Qemu-devel] [PATCH 19/22] tcg: introduce tcg_context_clone, Emilio G. Cota, 2017/07/09