Re: [igt-dev] [PATCH i-g-t 1/6] aubdump: Add gen8_map_range

From: Scott D Phillips <scott.d.phillips@intel.com>
To: Jordan Justen <jordan.l.justen@intel.com>,
	IGT GPU Tools <igt-dev@lists.freedesktop.org>
Subject: Re: [igt-dev] [PATCH i-g-t 1/6] aubdump: Add gen8_map_range
Date: Wed, 21 Feb 2018 16:43:41 -0800	[thread overview]
Message-ID: <87d10x3lc2.fsf@intel.com> (raw)
In-Reply-To: <20180221231905.15580-1-jordan.l.justen@intel.com>

Jordan Justen <jordan.l.justen@intel.com> writes:

> This function should allow us to only write the page table entries
> that get used.
>
> Cc: Scott D Phillips <scott.d.phillips@intel.com>
> Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
> ---
>  tools/aubdump.c | 41 ++++++++++++++++++++++++++++++-----------
>  1 file changed, 30 insertions(+), 11 deletions(-)
>
> diff --git a/tools/aubdump.c b/tools/aubdump.c
> index 700296f4..2e60e547 100644
> --- a/tools/aubdump.c
> +++ b/tools/aubdump.c
> @@ -382,12 +382,40 @@ register_write_out(uint32_t addr, uint32_t value)
>  	dword_out(value);
>  }
>  
> +static void
> +gen8_map_range(uint64_t start, uint64_t end)
> +{
> +	uint64_t entry_addr;
> +	uint64_t page_num;
> +	uint64_t end_aligned = (end + 4096 - 1) & ~(4096 - 1);

end_aligned = ALIGN(end, 4096);

> +
> +	if (start >= end)
> +		return;

Also check (end <= 1ull << 32) (ggtt is at most 4gb)

> +	entry_addr = start & ~(4096 - 1);
> +	do {
> +		page_num = entry_addr >> 21;
> +		uint64_t last_page_entry =
> +			min((page_num + 1) << 21, end_aligned);
> +		uint64_t num_entries = (last_page_entry - entry_addr) >> 12;
> +		mem_trace_memory_write_header_out(

> +			(page_num << 12) + ((entry_addr >> 9) & 0xff8),

This is a little obfuscated and comes out to equal (entry_addr >> 9) if
I follow.

> +			num_entries * GEN8_PTE_SIZE,
> +			AUB_MEM_TRACE_MEMORY_ADDRESS_SPACE_GGTT_ENTRY);
> +		while (num_entries-- > 0) {
> +			dword_out((entry_addr & ~(4096 - 1)) |
> +			          3 /* read/write | present */);
> +			dword_out(entry_addr >> 32);
> +			entry_addr += 4096;
> +		}
> +	} while (entry_addr < end);
> +}
> +
>  static void
>  gen10_write_header(void)
>  {
>  	char app_name[8 * 4];
>  	int app_name_len, dwords;
> -	uint32_t entry = 0x3;	/* read/write | present */
>  
>  	app_name_len =
>  	    snprintf(app_name, sizeof(app_name), "PCI-ID=0x%X %s", device,
> @@ -403,16 +431,7 @@ gen10_write_header(void)
>  	dword_out(0);		/* version */
>  	data_out(app_name, app_name_len);
>  
> -	/* GGTT PT */
> -	for (uint32_t page = 0; page < ALIGN(PT_SIZE, 4096) / 4096; page++) {
> -		uint32_t to_write = min(PT_SIZE - page * 4096, 4096);

Might as well delete PT_SIZE as it's not used now.

> -		mem_trace_memory_write_header_out(page << 12, to_write,
> -						  AUB_MEM_TRACE_MEMORY_ADDRESS_SPACE_GGTT_ENTRY);
> -		for (uint32_t i = 0; i < to_write / GEN8_PTE_SIZE; i++) {
> -			dword_out(entry + 0x1000 * i + 0x200000 * page);
> -			dword_out(0);
> -		}
> -	}
> +	gen8_map_range(0, MEMORY_MAP_SIZE);
>  
>  	/* RENDER_RING */
>  	mem_trace_memory_write_header_out(RENDER_RING_ADDR, RING_SIZE,
> -- 
> 2.16.1
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